In terms of his fertility I read so much differing opinions on the internet that we waiting until after she'd been spayed and healed before commencing in ernest. It was about four weeks after his op that they had very heavily supervised play dates. We got him done at Christmas, and she was spayed at the middle of February. So I'm guessing around 6 weeks in total. To be fair I glad we did wait because she became a nightmare in the run up to her spay. Poor Mister was hounded during those last play dates, where as he'd lost all interest lol.
Edit... Sorry it was 4 weeks after that the play dates started... They had around two weeks of dating before her op. Got my numbers the wrong way round. X