A neighboring region has a site with asphalt that sheds so much sand it might as well be a beach. It is very important to never, ever, get outside "the line" - especially once the marbles get into the mix.
I agree with Kevin. On the few courses I've run that "required" third gear, it was ALWAYS faster to just stay in second, brake early, hold a tight line, and set up for a fast exit.
I have also run courses that never required leaving first. Naturally, those courses will always be on fresh sealer
The Hoosier is not a drag tire. It has very stiff sidewalls. It may help to lower the pressure to 28 psi or so (whatever you can get away with without chewing up the sidewall). You may also have diff issues.
Regardless, there is no substitute for learning to modulate the throttle smoothly. Running in third will be
slooowwwww.