I’m not really sure if I follow what Joe said, did you mean transposing the song to the key of C, maybe I misunderstood you, it’s more than just transposing the song, you have to transpose all the bars that are not C, it sounds daunting but can be done quickly after a few sessions.
First I would say that I would not even attempt to make a style from scratch, to make a style from a midi file is do-able, I have been successful with making song styles for the past 12 months, the quickest method would be to find a style on the keyboard that has the feel that you want, then add an intro and a ending cut from a midi file, transpose to C and that’s it, intros and ending are just simple midis, I do all the basic work in my sequencer and import to StyleMagic, the only programme I need to use,
If you want to go further and cut the midi to make variations A B C D, then that is do-able also but takes longer, just making a song style using a Yamaha style and making a new song specific into and ending could be done in 1 hour, cutting a midi to make a full ABCD style would probably take 3 to 4 hours depending on the complexity of the song.
Re, transposing sections - Delete all unwanted tracks, just keep exactly what’s needed
You really need to listen to your midi and determine what going where, eg, Var A B C D
eg. Var A, - in your sequencer Transpose the midi to C, cut all tracks where you think VarA should start and where to finish, delete all other parts of the midi, everything, save this section, save and name it let’s say “Misty A’, lets say it’s 8 bars long, on my sequencer I can see the chord names as I run through the 8 bars, let’s say - 4 bars of C and 4 bars of F, now you have to use your markers to mark that 4 bar F section and transpose to C, now the 8 bars is in C, it will not sound good when you play it but the keyboard will control the chords later,
When your done with ABCD then load into StyleMagic, copy and past into ‘section manager’ ABCD. You can load A into ABCD or A into A&B and B into C&D, I sometimes have A on ABCD and different OTS on each one, just bring in a `tambourine’ or a ‘hat’ on a Mutipad where needed on a chorus or somewhere,
StyleMagic will sort out the Sint and all the midi to style business, you will have to study that yourself, I can only tell you that all the work in StyleMagic should not take more than 10/15minutes, assuming you have done the work in your sequencer.
Hope this is helps you little,
Pino.