With Mp3 192 or better 320 kBps settings you won't loose too much sound quality. With FLAC you'll end with about half the size, and no loss at all, but you and the receiver need the software to change them back to WAV or AIFF if you use a MAC. - NOUT
Thanx all.
Dana, I stumbled upon that Garageband/iTunes option just last night while searching Youtube ( 'WAV to MP3 conversion' ). I'll give it a try today. Be interesting to see what size file I end up with for a 3 - 4 minute song with 4 tracks of instrumentation within the Garageband file ( drum beat, rhythm guitar,occasional lead guitar and a little slide/simulated pedal steel sound ).The next song I do will have a vocals track also.
If I can get them down to Outlook email friendly size ( MP3 quality isn't the priority as it's only a backing track for home practice use )then I'm up, up and away.