I've raced mainly in the Philippines and we've basically got warm (hot!)/humid weather there..and we raced outdoors on an asphalt raceway.
Same thing there-- Sorex still is the choice of tires. 32's for AM racing, 36's from Midmorning to early Afternoon. 30's-28's from late afternoon to early evenings. 24's for night races.
Inserts -- I mainly like soft to medium compounds. Soft one's will give you better traction but the rubber wears out faster. Mediums will be a middlepath -- less traction but less threadwear..
Rims -- Speedmind dish rims!
Traction compounds also help...
And like PeteB said -- make sure you CA/glue them on the rims well..