you would only use a night drop if you are breeding.

if you are just keeping snakes, with no plan to breed them, i would go with an on/off style thermostat. ranco or johnson control make some very good ones, and they are cheaper then the proportional herpstat and helix. there are many threads around this forum that talk about all the features and stuff about thermostat. i'm sure someone will be along posting some links.

i use johnson control A419 and i love them.