Heat is not a problem for amaryllis, only sun itself. I have a similar weather, About 95-100 F each day, but they get only 2-3 hours of morning sun, all other time are in the shade. And they are growing and multiplying like crazy. If for some reason I remove a baby bulb from a pot and replace it with soil, new bulb will appear in a several month .
After several years , mine main bulbs are now about 35 cm in circumference, over 4 inches in diameter and continue to grow.
and bloom in the end of each winter.
You should use less a clay soil, soil from nursery that based on coccus, is one of the best
