I wish I could be there!
SHLBYGT is a great instuctor and we've logged a few hours together at Summit Point.
He knows his stuff!
As for the tires, my recommendation would be to start out on street pressures to form a baseline and go from there.
You will find that the big tracks are far less onerous on tires than an AX.
Smoothness is a bonus always, but I think you will be surprised at how quickly you pick up the line.
There is an old adage that states...
"Great autocrossers make great road racers. Great road racers make LOUSY autocrossers."
Take your time, don't let the "red mist" get the better of you and I think you will have a VERY rewarding experence!
Can't wait to hear the stories and see the pictures/video !!
Good luck and keep the shiny side up!!!!