putting the protaper atv mids on resulted in more handlebar vibes, really noticeable on the left side. I varied weights on the bar ends to no avail, and finally tried disconnecting the cross bar today. the vibes are now a non-issue.

Cross bar? So your aluminum handlebars are 7/8 diameter throughout, and not tapered up to 1-1/8" in the middle without a crossbar... My Tag Metals T2 tapered aluminum handlebars are great at killing the vibrations. I have no end weights, just Zeta handguards. There are no perceived vibrations in the hands or mirrors.