I have only had the 28" tires on VHT one night.  It was when they were 28X10.5 on the stickiest track on the planet.  I dead hooked, so my 60' probably sucked, and on the third pass I broke that axle, so I haven't even looked at the timeslips.  Since then I have bought some 28X9s, so perhaps I won't deadhook.  I'm setting up for roadracing now, so I won't have a 60' time with the 28s to report for a while-maybe in November.  I may 60' worse, I dunno, but to be able to finish the distance in the desired gear is super nice.  There's two ends of a track, you know?