I'm not sure what your goals are for having the roosters and pullets together. I'll sssume you want fertile eggs but there could be other reasons which might change my suggestions.
I'd wait at least until some are laying before I introduced any roosters. The boys are likely to be on hormone overdrive and the pullets will not be very cooperative, so it will probably not be pretty. Once a few are laying, they are more likely to accept the rooster's advances which makes it more tranquill in the flock. It is a shared responsibility. Often, not always but often, the rooster is a lot less violent if the hen does not resist.
When roosters are raised together in a flock with hens or pullets, they often work out their dominance issues when fairly young and are able to settle into a dominant rooster/subordinant rooster partnership and work together quite well to protect the flock. This does not always happen. Sometimes they fight to the death.
You don't have this situation though. Your boys have been raised together but separated from the girls. They have set up a pecking order (though from the fighting it seems they have not totally settled that) but they have not set up a flock dominance. (It is possible if the pullets are next to them the current fighting may be working out flock dominance, even as young as the pullets are.) Whenever you put two or more roosters together with the girls for the first time, expect some pretty serious fighting. Pecking order and flock dominance are different things. With both pecking order and flock dominance, size is not the most important thing. The spirit of the two fighting is.
I don't know how old the pullets you will be getting next month will be. With a total of 23 pullets, you will need two roosters to be pretty assured they are all fertile.
I can't tell you which rooster to get rid of or which to keep. If they were with the flock and dominance established, you could tell how they will treat the girls and each other. You are not there. You don't know how a subordinate rooster will behave if he becomes dominant. There is no clearcut easy answer for you. While I do think size difference between the hen anbd rooster is one criteria for barebacked hens, I think personality of them both is much more important. And it is hard to tell what the personalities of any of them, roosters or hens, will be until you are in the actual situation.
Not much help, I know. Good luck!
