I have a royal and use red heat bulb mainly as means I can see her and sets a better overall temp for her 4ft viv .
I tend to find that once her basking spot/hide is the right temp the rest of the viv sorts itself out nicely.
beware though snakes are so addictive one is never enough
[SIGPIC] my pets ..
apple, lemon bumble bee royal python
cookie & minty, staff & greyhound
butch & sundance ,bearded dragons
chaz & dave ,budgies
sooty & sweep, polecats
goldfish and gerbils