Mazda, as far as Hoosier slicks go, the rating system goes from R25 (softest) to R 75 (hardest). Obviously, the softer compound is better for autox with our lighter cars, but probably not so for track days. Compromise to R35??
Don't know how the weight of your car will affect the compound choice. Maybe you can buy a set of used slicks for the track days. I understand that you can pick up some good usable tires from race teams, at a reasonable price.
Or you could look at the Hoosier R6-A6 Dot tires. R being track, A=autox
Looking forward to seeing your beast run. Tom