Hi JCL,
Some thoughts.....
If there is a good style I will use that, but some midis have so many changes and effects that can take playing to the next level. However, some would say "you are then in a straight jacket - always playing the same piece the same way more or less". I don't totally agree as that is exactly what playing along with a style is
The benefits for "My Way" for example are the gradual volume increase and build up part way through. You can't do that without a lot of fiddling or volume pedal etc. Extra instruments and drums come in - so you would need to code up multipads. So then you open up a whole new world.
I like playing along with midi files - for a few of the songs. Finding a good one is the first step. I like to have the words and chords on screen. Chords are midi events and sometimes when you edit a midi on a PC they can get stripped out. PSRUTI is great at guessing them and then if there are any corrections, they are easy to see and make (on a PC!) You can also add text/reminders to change REG or something like that. This gives some consistency. Some midis you can play along to a style which then overwrites or appends to the midi depending on what tracks are in use. Sometimes the combination of midi and style can sound stunning - sometimes not.
Why edit midis - cause many of them are not all on track one, or not all of the melody is on track 1. So you are part way through a midi and you can't see the melody notes. That means you need to copy them from one track to another. So let's say the main melody is on track 1 and then on track 11. Oh yes, some midis make finding the melody a challenge
You copy the relevant section from track 11 to track 1.
The next problem is getting sheet music that matches the midi. I sometimes do that as it is easier to see what is coming up and exactly where you are in the music. "Let Me Entertain You" by Robbie Williams is an excellent example. I ended up colour coding some of the changes, repeats. loops etc and I now enjoy the technical side as my playing is impeded a bit for other reasons. The other thing is that you will rarely get the music in the exact same key with all the same key changes as in the midi. So you have programs like notation composer £££ or musescore (Free!) and there are probably others. The first can create a fake book lead sheet very quickly and you can copy across tracks, but costs way too much. You can do the same in musescore (import midi etc) and then hide the instruments you don't want. There is a chordfinder plugin which is quite good at guessing the chords. I think it is stunning, but steep learning curve. The print outs are better than notation comp. imho.
The next stage is turning off channel 1 and/or other channels (you mentioned the chords)- well that is only 1 option. So for example, if there is some timing that you are not sure of, then sometimes it is better to change the melody instrument to flute or clarinet and set the volume to 30. In other words something that you can just hear if you are not playing anything else. MixMaster is quite good for that. You can still switch the channel off on the Tyros if you want to, but that sometimes helps. Also you can change to string and put lots of echo on, which again can be interesting.
So to your point of switching off the chords. Typically backing will be split across many channels and you can switch them all off if you personally want to play the chords. This can also be interesting if you have a Jazz piece such as Fly Me To The Moon as that will have a few chord alternatives and you might want to play differently. I have never seen that on Yamaha or any other midi, but again it is something you could add as text with PSRUTI. I keep mentioning that as it is one of the few programs that doesn't screw up midi files and I won't mention the ones that do.
One trick that you might be missing as you mention splitting the keyboard is that you can do that with registration changes and then assign those changes to a foot pedal. So sometimes I get a bit lost when playing stuff in the "third sector" so I will reg shift the keyboard on a foot pedal to make the sound changes in "2nd sector" and then reg shift again to reset it back. It gets more interesting than that as you can set up a "registration sequence" (should be in the manual) and then completely change the keyboard setup in each of the sectors when you shift change registrations. So, you can have loads of changes within one song or melody.
Hope all this makes sense and helps. I find all this fascinating. All the free programs I mentioned are great at what they do, and my thanks to the team and authors.
- Andy