I totally agree - its so down to the individual cat. I originally had just one cat, Tilly and she was about 5 years old when we got Billy. She has never liked him and despite his best efforts, she won't take any notice of him. He soon gave up and played in the garden with the cat next door instead. When my mum passed away, I took her two cats (which were the family cats anyway) and because they were 16 at the time, Tilly seemed to respect their 'oldness' and remained respectful towards them. No fights or anything, a very easy introduction. Billy tried to play with them too - no luck (poor Billy) They all ignore each other now. When our new kitten came along she was, and still is, universally ignored by all cats except Billy who plays with her. If she is lucky, one of the oldies might sniff her but then they ignore her. Maybe I have had an easy time of it but I haven't had any real problems and thankfully, no runaways.
I think you should go for it and see what happens coz you won't actually know the reactions until you do. I don't know that there is a lot of difference between a female cat and a castrated male cat - if ya know what I mean :wink: so maybe you have a choice!