You also can make UserTracks even if you don't have Band-in-a-Box or RealBand. To do this, simply download the "Making UserTracks without Band-in-a-Box or RealBand" template file
Where is this file
This is now located at
http://www.pgmusic.com/usertracks1.htm
Can the style contain midi and\or realtracks
Does it have to be an official biab style or can you use an original or 3d party style
Since the biab .sgu file is stored with the usertrack must the user of the style have that style or realtrack used in the style on their system
Yes, the style can contain MIDI and/or RealTracks, and yes, you can use an original or 3rd party style.
For someone to use your UserTrack with the same .sty that you suggest, yes, they'd need to have that .sty. BUT, if they don't have that .sty they can use your UserTrack with many OTHER .sty files that they DO have.
The best way to show off your UserTrack is to actually do a render or two of the UserTrack in action with your choice of .sty.
I hope that helps.