No worries about him skipping food, ball pythons areally notoriously fussy eaters. Stick to trying one method of feeding per week, trying multiple ways is only going to make each method less likely to work. If he doesn't take the rat when you wiggle in in front of him, leave it in with him overnight and toss it in the morning if he hasn't eaten it. He'll be hungry eventually, but don't be surprised if it takes him a few weeks or even a month or two before he decides he wants the rat.