Hi, how exciting
I hope everything goes really well. We did this recently, they spent about an hour together at the rescue and then we brought them home. As it was a long journey they had that time to get used to each other too. It was love at first sight and they got on great right away. I did put food in straight away and had no issues, but I don't know if that's the done thing or not. Sadly we lost him to illness in just a few short weeks.
I'm not sure about the op. Ideally I'd probably want to give them longer to recover, although perhaps not practical. But im sure others will be along who can advise x