Hi! My first post... Hope it's helpful.

Did I read that one cause of belt problems was that the tail was not perfectly, uh, aligned... as in: tail pulley shaft perpendicular to the vertical, driven shaft and pulley up front.... resulting in the belt running to one side of the rear pulley. I realize the belt is flipped 90 degrees on installation... just makes it a bit more difficult to adjust.

Not unlike a belt sander where the belt runs over to one side, but can be brought to a centered position with careful adjustment of the belt tension adjusters... which can send the belt running right or left if not tweaked perfectly.
In our case, just loosen the tail clamp and rotate the assembly minutely. Will this lessen the problem?

This is one thing I'll be watching as I'am building mine.

Lee