I wouldn't worry too much about getting snake mites from your wood unless you're getting your wood decorations from Africa. Or a shop that has mite infested reptiles. Unless you mean wood mites eating his decorations.
You could have used a drainage layer if you wanted and gone with over head heat or keep your ambient room temperature in the mid 80's. Not that there is anything wrong with how you're doing it if it works for you. Plenty of people use overhead heat like radiant heat panels or keeping their reptile rooms ambient temperature warm.