All stems should begin from the very start of your session (bar 1, beat 1) so they stay in sync.
If you send a Pro Tools session, be sure to compile/consolidate the audio files on each track into one single file that starts from the beginning of the session. It saves time and potential confusion, particularly if there are tempo or meter changes in your track.
OR, if that’s too complicated, try this…
Send an MP3 of your song and include a one bar metronome count in that doesn’t have drums in the mix. We’ll discuss the kind of files you need to get back from me.
Send your files using one of many free file transfer services. I use WeTransfer, but other options include DropBox, Box, etc.
