Obviously, depending on the scenario, there are 2 stand-out approaches:
If you can send the files via internet, I would think that your best approach would be to use some sort of mixing software (ProTools, etc.). If you have wav files, you can edit/mix/etc. all on your software, and just add tracks as necessary. Obviously, this won't work if you're sending tapes via mail.
So if you are sending tapes via mail, I would say just record the tape (if this is the case) into your digital 8 track. It's not perfect, but it will still get the track onto your 8 track.
My old band's bassist recorded our demo. (It was a pretty horrible demo-recording-wise, not music-wise). I wanted to play around with the tracks when I first got my digital recorder, just to see what I could do with it, and improve my vocals. I wanted him to send me the wav files, but instead, he burned the individual tracks (except his shitty, lame-ass bass lines---as if I actually wanted them...he was a real dick) onto CD-R as audio tracks. I had to record them from the CD's into my recorder. Then I recorded new vocals and had a friend record new bass lines to the songs. He wanted to make it difficult for me, but I still came up with something that made it sound 10x better. After I got the tracks, I never talked to him again...he was such a dick....and not even a good bassist. Let alone a horrible producer.
The moral of the story: I have no fucking clue, but I'm glad I came up with something better than what that asshole did. LOL. Thanks, you've been a great audience.
