I have come across the same issue many times with mixed time signatures within a song. I have found two solutions, just in case the registration idea doesn't work out properly.
Actually our fellow forum member (Jørgen Sørensen) who developed a lot of our custom software that we use on our Yamaha keyboards has created a program that does exactly that, place a different time signature with a different style Main Variation. I have the program and fooled around with it a while back, however I ended up using my second solution that I will explain later.
The program is called, Style Time Editor. Check link below. Jorgen even has a sample style to download from this page.
http://www.jososoft.dk/yamaha/software/stytime/index.htm
You can try it, but I ended up using a second method. Even if I managed to create such a style with different time signatures, it would be too taxing for me to press the correct style variation at the exact time without error. Maybe not such a disaster between a 4/4 or a 2/4 timing, but your song would come to a crash if you mixed up a 4/4 with a 3/4 or in one of your hymn examples, a 5/4 with a 3/4 timing mix-up. If you are precise, then maybe a great solution to create a variable time signature style.
What is unique to Yamaha is their Free Play styles. Meaning, no strict tempo is required. I created several modified variations that I use for the exact purpose you described. Some sustained Multipads work well with a Free Play style as well. Even a guitar strumming pattern Multipad that cycles very two beats can work with both a combination of a 4/4 and 2/4 song. A suitable Free Play style or tweaked one within Style Creator can work no problem with that 5/4 and 3/4 song. You can get nice fills and style breaks manually at the correct times or trigger a one shot Multipad fill at the correct time. Several Free Play styles in the Genos or available from YamahaMusicSoft.
If I find time this weekend, I'll take a stab at one of your PDF songs and post a MP3 of my results using one of my Free Play styles.
Regards, Marcus
Edit: Forgot, Jorgen's Style Half Bar Fill Creator could work for your 4/4 and 2/4 timing song by pressing a 2/4 style fill at the correct measure to keep the timing correct in your song with this combination of time signatures. Here is that link.
http://www.jososoft.dk/yamaha/software/filledit/index.htm
I didn't find time last weekend to create an audio demo of my Free Play style solution, but fooled around a bit during this week to make a few audio demo examples on how I would deal with mixed time signatures within a single song. I chose to try the "10,000 Reasons (Bless the Lord)" song because the PDF had the lead line, chords and Lyrics and both the 4/4 and 2/4 time signatures. That's pretty much all one needs to work the magic of these modern day arrangers, especially the new Genos.
Never hearing the song before, I found a piano part that helped me flesh out some arrangement ideas and to integrate a customized style(s) to suit. A Praise song is in my wheel house, so quite easy rearranging and recording with the Genos. I found my Right Hand piano parts from the link below.
https://musescore.com/user/94620/scores/124550At any rate, my first demo
(10000Reasons(PowerPopBallad+vocal).mp3) is perhaps my choice on how I would perform this Praise type song. This rough idea was recorded me playing live to a custom style, OTS and multipads. The Multipads have two beat guitar patterns that would fit for both the mixed 2/4 and 4/4 time signatures. A style "Break" can help with the transition between the timing events. I added a little VH in the choruses and recorded a couple of verses.
10000Reasons(PowerPopBallad+vocal).mp3https://app.box.com/s/8v9s33bmtl654oysteuohzi7n8zij89jThis second demo is just showing another style choice that works with the song.
10000Reasons(PowerBallad2).mp3https://app.box.com/s/c5l3csb4mtmm6lxzxpqbjbadwnzjrgz7The third demo is my concept of creating a Classical type version of the song. I am using the Genos "String Adagio" style, custom Ensemble voices, and choir Multipads. All my songs are arranged to play live and are called up through Performance Registrations on my Genos.
10000Reasons(StringAdagio).mp3https://app.box.com/s/iwdwbtptf0l7u9pgg5w8ysdb8zp0s6dfA Free Play style can work with this song, but not my first choice. However, an interesting version can be created in this demo. I chose the xt5_FreeEvolution Free Play style I purchased from YamahaMusicSoft a while back. Sort of a contemporary twist to the song using this style. I customized it in Style Creator and saved it with the 73 Tempo. Reason being, although the style can play without a strict tempo, the rhythm type Multipads are slave or clocked to the style. So by setting the Free Play style at a strict tempo, the Multipads are at the correct tempo. Multipads "OrientalPerc4" are linked to the style. You will notice the drum beats appearing during parts of the song. Since the drum patterns run every two beats, they fit within both the 2/4 and 4/4 sections of the song. Again, I use the style "Break" for the smoother transition between the two time signatures.
10000Reasons(Freeplay).mp3https://app.box.com/s/ffua8dpeq9pdlmkc3k6dod3kgtyz59v1Hope the above helps in addressing different time signatures within a song.
Lastly, here is a list of a few things that made me buy a Genos.-The best sound quality ever on any Digital Arranger Workstation.
-CFX piano voices, the lush Kino Strings or the punchy Revo!Drums.
-AEM (Articulation Element Modeling)
-C7 Grand Piano (Perfect for production piano with my custom arrangements.)
-Genos features a diverse range of content library, including 1,710 instrument sound, 550 backing patterns, 216 arpeggios, lots of new Multipads containing exclusive Genos Voices and DSPs.
-Genos boasts unprecedented DSP power.(Love adding individual channel insertion DSP effects to my MIDI songs.)
-Using the same VCM technology as Yamaha’s professional high-end mixing consoles with the tools to create the perfect sound.
-1.8GB of user flash memory with high speed reading/writing for your own Voices.
-Select and change parameters directly with the new 9" colour touch screen.
-10 Registration Memory buttons.
-New S/PDIF Digital output without any loss in audio quality.
-New 32bit Digital Audio Converter (DAC) provides high quality defined sound across a wide frequency range, ensuring Genos always cuts through the mix. (A Toronto sound engineer once told me that the (DAC) in the Tyros series was highest quality amongst the competing brands. The Genos take sound quality to yet another level.)
-The FSX keyboard features a premium action with aftertouch. (Such a pleasure to play and add feel and expression through aftertouch action.)
-Four Sub line-out connections.
-Yamaha Expansion Manager (YEM) with support for WAV, AIFF, SoundFont and REX formats.
-Genos, super light at 13.0 kg (28 lb, 11 oz).
-Polyphony at 256 (max.) (128 for Preset Voice + 128 for Expansion Voice). (Have not yet experienced any note drop-off even with my most complex 26 track arrangements.)
-491 Pro, 39 Session, 10 Free Play, 10 DJ styles.
-Audio Phraser software is amazing. Create your own Audio Styles.
-Added a new function: Voice Guide.
-Play multiple Audio Link Multi Pads simultaneously.
-Play an Audio Style file on the USB flash drive directly.
-Edit Audio Styles with the Style Creator function.
-Select the Drum Kit of the "Expansion" folder on the Drum Setup window of the Style Creator.
-Record the sound of Audio Style and Audio Link Multi Pad playback with the Audio Multi Recording function.
-You can now select whether playback of a Multi Pad stops in the following cases, on the Style Setting display:
・When Style playback is stopped.
・When the Ending section of Style is played back.
-Select whether playback of Style and Multi Pad stops when MIDI Song playback stops, on the Song Setting display.
Perhaps I could go on to over 10,000 reasons why I bought a Genos.
Regards, Marcus