I have silkies, more boys than I need, I keep a bachelor pen for the ones who'll get along, and just 1 boy per breeding pen.
I haven't tried doing 2 boys in one pen with hens as I have them color separated right now. I've had some spats through the run fences, mainly with the large fowl. The boys can sure get the hens riled up and upset. I haven't had any injuries though so I just let them get it out if their system, the boys eventually loose interest and wander off (except for the bantam Ameraucanas, they have no quit whatsoever).
I think keeping a double fence between them for a few weeks is your best bet and maybe try creating a bachelor coop and just introduce 1 boy when the time comes.