My only snake that eats in shed is my King. But he'll eat anything anytime. But his last few sheds I just waited. He certainly won't miss the meal and always happily takes it post shed.
I used to offer each of my new snakes ONCE in shed. If they refused (which all but the King have) I never offered again in shed. I just waited.
Now, I honestly don't even bother trying with my new additions. I just wait them out. No wasted prey and I never get post shed refusals. It seems they're always hungry after a shed.
They're efficient animals, so I know it does them no harm to wait a few extra days to offer food.