Oh, and I forgot, Track Day organizers and track owners don't like antifreeze, Antifreeze ESPECIALLY in high concentrations does not evaporate quickly when it gets onto the track from a leak or other source. It will leave a slick film much like oil and must cleaned up with oil dry absorbent. They will bill you for that.
So some will require water only. I tried different concentrations and I think that up to about 1/3 antifreeze dries pretty fast and would be ok on a hot day as long as you don't blow off a lower hose and dump 3 gallons on the track all in one spot. The best advice I can give for track cars at first is to run all water at the track.
I change my coolant every winter when I do all the other fluids including brake fluid, engine oil, and GRBX oil. I open my coolant drain plug, drain it all out, refill and drain with clear water, and run the electric pump until it comes out clear then drain again and refill with my coolant blend.