I write music with many variety of instruments but the number of instruments I use requires more than 16 channels. So I sometimes decided to make 2 or 3 staffs using the same channel and instrument due to similar sounds.
E.g: Set Piccolo with the Flute sound and tranposing it an octave higher OR Set Tuba with Trumpet sound. That's one of my own suggestions but I'm basically eager to have every instrument I demand to have thier own channal and instrument.
I really want some suggestions on how to use MORE than 16 channels!!!
Set up more than one Device(s) used by play back (http://www.noteworthysoftware.com/nwchelp/TAB_OPTIONSMIDI.htm). Assign the same channel to as many staves as you have devices and assign a different device to each. Most SoundBlaster cards support at least 2 synths + MIDI Out. Connect something to MIDI Out and add a Yamaha softsynth and you can have 60 fairly high quality instruments. No one else will be able to play your creation without duplicating your setup, but if you just need the voices as an aid to composing or arranging with the ultimate goal of producing an MP3 or hard copy score, this won't matter.
You get 16 channels per MIDI device. You can use more than one MIDI device, thus expanding the number of instruments that you can use.
If you are never using more than 16 instruments contemporarily (yuk! Wagner?) you can assign the same midi channel to a couple (or more) instruments that never play together, then insert an instrument change before any time those instruments starts to play.
Possibly you have to set also some MPC like pan, expression, modulation etc.
That's an old trick used with an old GEM WK2 keyboard that didn't allowed more than 5 patches contemporarily.