That should work but i personally prefer to keep it a little cooler. With 85F ambient on the warm side, i would probably turn the flexwatt down to 88F or so. I think 85F warm side ambient and 92F floor heat is just overkill.
Best bet is watch the snake, if it never uses the warm side, then its probably a little too warm...or the cool side is plenty warm for it so it doesnt need extra heat.