Mine is an X73 car, and for the time being, I can't see myself running anything stickier than the MPSS.
I just ran HPR in 102 track temps, no humidity, plus altitude and my oil briefly hit a high of 288 during one session, but was mostly in the 275 - 278 range. I change both the engine and diff oil same time around 15 - 18 track hours depending on conditions. When the car has been running in the above conditions, I shorten the cycle a bit.With all the track days I've run in the last year as well as others on P-9, if it was going to happen, it would have happened already. I don't recall anyone posting an engine oil starvation issue.
Oil cooling however is another thing. I ran Sebring this past weekend and I regularly get my oil to 270-277 deg. F on a ambient track day temp of 95F. I just change the oil more frequently.