Yeah, there's no "right" or "wrong" time of day to handle them. I normally try to handle mine in the late afternoon/evening because I've found that she usually decides to start roaming after I put her back, but you can handle them during the day with no problem too. The only real time you should definitely avoid handling is for the 2 days after they've eaten, but I'm sure you probably already knew that

I'm not sure exactly why he struck at you. If it was in the middle of the day, you could have startled him a bit if you woke him up. Some bps are more defensive about being disturbed than others. The only other possibility is that he's going into shed since a lot of them tend to be more crabby around that time, but it sounds more like he was just scared of the "big dark thing" (the hide) when you went to put it back over him. It doesn't sound like you did anything wrong though.

The only thing I would recommend is that next time if he starts to ball up just pick him up anyway. Yes, it does technically mean that they don't want to be picked up, but he will eventually come out of his ball after he realizes you're not going to eat him