I think it will be telling when you swap over to new yellows. (make note which end the fast drivers are wearing out first, front or rear tires) I would suggest going back to a medium hub with the new tires and tune from there.
If it does continue with new tires than I would suggest doing the things to add rear grip by narrowing the rear, going to longer hubs, lower the rear ride height (axle up), and adding another set of seat struts.
November 15-19, 2017
Las Vegas, Nevada
SKUSA SuperNationals 21
2018 Events TBA