Lou-first off, watch the weather carefully and don’t be afraid to back way off during the race to prevent significant heat related illness. You would benefit from a quick listen to Tri-talk.com where Coach David Warden did a nice piece on warm weather acclimatization. The meat of the coconut was an hour a day for ten days in the heat and then the benefits, increased sweating, lower electrolyte loss in the fluid you do sweat, cooler skin temp and more blood away from the skin to achieve a better performance.
Tom Warren won Hawaii IM #2 in 1979 by training in a sauna. You need to do your best over the next several days to at least try …but use your head. Good luck.