We were told by our local farm we could switch some out depending on how many roosters we got but I’ve grown attached to them, they have enough space in our yard but I’m not sure if it’s enough for two roosters to keep distance. And I heard of overmating too.
Can you keep two roosters together? People do all the time. Sometimes it is successful, sometimes not. How much room you have is just one of the criteria, individual personality is also very important. Raising them together sometimes helps, sometimes not. Your expectations and tolerances can play a part, what I see as normal behavior may cause you great distress. In my opinion, "if" the boys are going to fight over girls they will fight over 30 as much as they will fight over three. If being the operative word. You can possibly have over-mating or bare backs regardless of ratio.
Why do you want a rooster? What are your goals that requires a rooster? The only reason you need a rooster is if you want fertile eggs. Everything else is personal preference. Nothing wrong with personal preference, I have a few of those myself. But those are preferences, not needs. My suggestion is to keep as few boys as you can and still meet your goals. That's not because you are guaranteed problems with more boys but that problems are more likely. That includes the possibility of human aggression, not just how they interact with each other and the girls.
To me, your goals are what is important, not mine. That is your decision to make. I agree that if you keep 2, 1, or even none it is a good idea to have a place you can immediately isolate one or maybe more from the flock. You never know when you may need to isolate an injured bird or something like that. But if you have one or more boys, regardless of numbers of girls, it is even more important. And when they go through adolescence it is even more important.
Cockerels are a trap. The boys are bolder and more adventurous. They are the ones that you notice because they have an outgoing personality. Those are the ones you fall in live with. Those ae the ones people pick out at the feed store because they show personality. If you are going to get rid of one or two boys, I suggest doing it as early as you can be sure of the sex to reduce becoming attached. Your girls will show you plenty of personality as you get to know them.