
Hi Helen,
having two same sex dogs doesn't need to spell disaster - I've had two entire males living with an entire bitch at the same time and one entire male living with two entire bitches - no problems with either combination :)
Personally for the average domestic household I always recommend one of either sex as this is the least likely to ever be problematic (providing one, pref bitch, is neutered of course).
If you do feel that your heart's desire is another male, I wouldn't recommend doing a pre-emptive strike on Hamish's bits

Until you get your new puppy and it has reached the adolescent stage and beyond there's no way of assessing which (if any of them) will be top dog :)
Regards, Teri