What wattage ceramic heat emitter should I use for a 10-gallon corn snake enclosure?

Hi corn snake lovers, I am planning to add a CHE for my corn snake. I live in a place where it gets very cold during winter, and a heat mat alone isn't enough to keep the hot area warm. Currently, the hot area temp stays ~26.8C (80F) with the heat mat on, low for proper basking. I want to get a CHE but I'm not sure what wattage would be appropriate. My enclosure is a 10 gallon tank. I don't want to overheat and risk burns, but I also want a reliably warm basking spot. I will be using a thermostat. Any suggestions or recommendations for the CHE?

I appreciate your helps!