You'll likely be pleasantly surprised at how much easier track miles are on tires compared to autocross, especially on a lightweight "momentum car".

Where you might see 100 autocross runs on a set of tires... what's that, maybe an hour and a half total? You'll easily get 8-12 hours of track time on the same set of tires.

As an example, when I did One Lap this year, my car saw 4,000 street miles and about 30 minutes of track time each day for 8 days... a total of 4 hours of track time. At the end of that, the front tires were about 50% worn, and the rears showed no significant wear at all. So, with proper rotation, those tires would have been good for up to 16 hours of pure track time!