hello,
I would:
1. switch to medium rats. 1 every 7 days.
2. I would also strongly recommend you switch to a UTH controlled through a thermostat.
better for the snake and will also help you get your temps up slightly
Questions that will help people give you the best advice;
1. what are you measuring the surface temps with?
2. can you post pictures of both the animal and set up?
The way you have things now I’m sure the snake will be 'ok' but you can take
steps towards getting things really spot on. Congrats on the snake!!!