I'd wait 2 weeks since the day he regurgitated. Glad everything turned out well!

I'm also amused at the waving hand in front of his face thing LOL. I wouldn't recommend doing that, unless you want to risk getting bitten and wrapped.

By the time 2 weeks pass, and you see him "exploring" the cage more frequently as if he's looking for something, you can be sure that he's hungry then.