Uncle Scotty , Which brand of tire do you currently have? I'm curious ( a thirst for more knowledge i guess).. I completly agree that a 245/40 would be optimal. Can you tell us why you dont like the 235/40? Too stiff? I know that you really have to vary your pressures (more than normal) to get a different reaction out of a tire because of sidewall rigidity.
To be completly honest with everyone i would much rather run a RE01r than the Hankooks or Falkens but they are just too pricey for me. I love to spend money on my car and have spent a ton on tires in the past, i just learned that with dialing in the proper alignment / tire pressure adjustment i can get a good reaction from a "tad" lesser tire and save a bit of money in the process..
I tend to run 110% of what the car can handle on the track and probably 95% at an autocross. It seems to eat up tires quicker than most..
Thus the reason for staying with Hankook and going slightly wider.