Supplying heat for my gopher snake

[Bandit]

Hey everyone, I just purchased a 40g breeder for my little gopher snake and I was wanting some opinions on how I should heat the tank. Currently, he is in a 10g with a heat lamp. Here are the two options I'm thinking of:

1. Heat lamp as primary heat source with a small UTH as a secondary source mainly for night time temps. In this case I'd get a low-wattage UTH that doesn't get too hot at all.

2. Larger heat mat which would likely be 12x12 or something like that. Since it would be the only source of heat I'd get a more powerful one and then a temp controller of some sort.

Let me know what yall think?