It sounds like you are doing all you can. Just keep a constant eye on the setup and you should be fine.

I am fortunate enough to have an entire room dedicated to my snakes - thank god because my husband runs the air conditioning also - I keep the air vent closed in this room and it stays about 80 degrees all summer long. Now in the winter - I have to supplement with an oil filled heater to keep the room warm enough because my husband doesn't want the rest of the house at 80 degrees - lol

Oh the things we will do for our snakes