I am not sure what your set up is, or if you have your chicks in with your laying flock as of yet, if not, you probably have two set ups. Which is good. The pullets will really start to be harassed by the juvenile roosters. Roosters are ready to be sexually active long before the pullets.
If you are going to keep the senior rooster and the rooster you keep out of these chicks together in the same flock, you need to get the chicks in amongst the flock fairly soon. Yes they are smaller than the full size birds, but if you set up some hide outs, a couple feeding stations and some extra water it should be ok, mainly as you have a lot more chicks than layers.
At this time, you need to really examine your roosters. Check their feet, they need to be even and with straight toes. Pick the bird up and feel the conformation of the bones of the body. When you pick up the first one, you will be able to tell that their are bone, but not much else ;-) However, pick up the second rooster and compare them, then you should see a difference. Check their skull shape, their keel and the shape of their wings. Look of the standards for the breed, and check these birds to that. You probably won't have a grand champion, but do look for a bird that shows regularity in sizing and shape.
So when you pick your best two, pull the other two chicks to where you had the chicks, feed them well, limit their free ranging, and in a couple of weeks, at about 14-16 weeks, fire up the bbq.
In the meantime, take a cup of coffee down, and watch your flock. One of the chicks you will like better, keep him and put the other with the boys in the bachelor pad.
Now, this is not a absolute this will always work plan. Some flock masters will allow an adolescent rooster to grow up in the flock, and be the sergeant of the flock, out on the fringes. Some young roosters will accept that role. However, some roosters won't tolerate another rooster. A foreign rooster will really trigger off fight. That is why I suggest getting him into the flock asap, so that he grows up under the leader. Sometimes this will work very well for a long time, and then there is a big fight. Sometime the leadership changes, sometimes it doesn't. Sometimes that settles it, sometimes they will fight nearly all the time until one of them is dead. Roosters are a crap shoot.