I'm sure they will be fine. I was just in your place last Thursday with R&R and it was hard not to worry. Rocky was back to normal in about 36 hours. They kept them overnight and both slept a lot the first day home but the second day home was business as usual and he hasn't stopped since.

So far no noticable changes in Rocky but it will take a few months for the hormone levels to drop significantly to notice a change in behavior or temperment. He's already the sweetest kitty in the house so if he gets sweeter, all the better.