My ball python has been eating jumbo mice for a while now and I believe he is too big for them now and needs something bigger. He weighs 676 grams. I've tried switching him to rats in the past and he always ends up losing a bit of weight from refusing to eat. I've tried scenting the rats and I've gotten him to strike at rats before but once he grabs it he immediately lets go and looks as if he had been hurt. Like he twists around as he pulls back? last time I tried to switch him to rats I gave up and tried to feed him a mouse but it took a few weeks to get him to eat a mouse after that. Both times I've tried to switch him to rats in the past he never showed any interest except for the first time I showed him a rat and he thought it's a mouse but then freaked out when he realized it wasn't.
I'd like to switch him to rats but i'm not really sure how. I know people say to just keep trying even if it takes months but I'm worried he will lose too much weight. He seems to lose weight kind of fast? Is there a way I can switch him to rats without having to worry about him starving himself?
Also is there a way I can help him put on a little weight? I think he might be a little underweight and I'm not sure if I should try feeding him mice more often or if I should try feeding him two mice instead of one.

Thank you for your time
I really appreciate you helping me out with my dumb questions