I used to race an SCCA ITA car, and had NO budget for a trailer and truck in my first season, and NO space for tires, so I drove on them. 3 hours here, 5 hours there, etc etc . All season long from April to October. Went through more cars and motors than I did tires.
Toyos were the choice. (Nitto is a current equivalent).
My results were decent, (generally 5th in a pretty competitive ITA field of 25), but lap times suffered, of course.
I'd say my current version of the car is 4% faster lap time, (Its a lap record pace car now) and of that half is the tire, the other half the driver and setup. Essentially, on a Minute or so lap, expect about (ABOUT, LOL) a 1.5 second drop just from bolting on Hoosier Rs and setting them up right.
But you can NOT drive the Hoosiers all over the place....

Hugely dependent on the car, and the driver.
A balanced car, easy on tires, like a Miata with a smooth driver can go dozens of weekends, probably.
A car with a heavy front end, or misaligned camber, or a clumsy driver, can cord a corner or flatspot them quickly.
I prefer to think in terms of sessions.
My Hoosiers last me maybe 10 -12 sessions. (Well, they can go further, but they are Toyo speed at that point)
Toyos seem to last the guys running them 25-40 sessions.
YMMV!!

I ran NT 01 on my cayman H-class for DE's and advanced days and got over 45 sessions on them. tire was a slick (all the tread was gone) at the end of the season but probably still good for a few more days. I have a new set for the coming season...awesome tire for DE and ery vdrivable on the street (not in pouring rain of course but damp is OK)

Just wanted to report back, and thank you guys for your advice. I did get a set of NT-01s, 225-45-17 and 255-40-17. Drove them to the track and back! Very good tire, took it a little easy the first couple laps of each session to allow warmup, but they felt great, stick was really nice. Very predictable, good feedback, and a great value as well. Have only driven them in the dry, interested to see what happens should I get caught in the rain to or from the track. Next up is Road America, will give them a good workout there.
dhc