Not eating anything except live

I bought my ball python from a breeder in February of last year. I had him up until about August when I had to temporarily re-home him due to moving 1000 miles. I got him again in December. I always fed him live large mice because he wouldn't take a f/t as much as I tried. But the girl who took him said he ate very well and whenever she offered food. Since getting him back, I've fed him several small live rats. I've also tried f/t rats that he never even glanced at. I figured it was because he wasn't a fan of rats and tried f/t mice.. same thing. I've tried f/t from several different companies. He recently shed and pooped just fine. I rarely handle him.

Up until last week I had him in a 28 qt bin with paper towels, a hide and a water dish. When I weighed him he was 550 grams. I believe he is a little thin. I switched him over to a 41 qt several days ago (mostly to give his much more secure tub to my lab) and he's on Aspen as of today. I have him on heat tape hooked up to a herpstat two. Temp is set to 95 and is directly on the tub but my temp gun reads a little wonky on plastic.

I am not able to find a constant supply of rats. I can't keep more than one because I'm very allergic and do not have any outdoor space/garage to keep them. Currently I have to drive about an hour one way just to purchase one live rat. I've contacted the girl from before and she didn't do anything special or different. I'm at a loss for what it could be. And I really don't want to re-home him.

Any ideas to what could be the issue?

All I can say is that 95*F is too hot.

I am working on the transition myself. My breeder only fed live and the first time I tried F/T he took it. Then he showed no interest. I offered a couple fresh kills. The first time it took a while for him to take it. After a few he started hitting them as soon as I put them in. I think he is in shed cycle so I haven't offered a F/T yet but the way he has been eating the fresh killed I hope now he will take the F/T just as quick. You might give that a try.

Did she say what he was eating for her and how it was prepared/ offered?

**ETA**

remember you just totally changed his environment so he may need some time to settle down and feel secure again.

I just messaged her. She said she heats them up in a ziploc bag in hot water the same way I do. She sent me a picture of his setup and they look almost exactly the same except her tubs were not clear like mine.

EDIT: I waited a week to try to feed him after changing the tubs. And the only thing I have changed before then was the paper towels whenever he made a mess. I added the aspen after trying to feed him.