I don't have any Welsummers' but a story that may be of interest to this post.
I have a Del rooster Nick and he was the only rooster. Full grown dancing with the girls and all. He was in charge of a flock of 19-20 hens various breeds. Included in the mix was Cowboy Curtiss a bantam friz. Both would dance with the girls and run to knock the other off, but they got along ok.
Then I got Eric and his 3 hens as young chicks. CM's. Eric and his girls stayed in their part of the yard not going near the other flock unless bread was being thrown. All in the same coop but when out in the yard seperated by choice to two flocks.
Then I seperated the flocks to seperate parts of the coop. They could see each other and hear each other but not mingle. Eric did get big.
Well when I decided to let them all out as before thinking they would go to their seperate flocks, I was wrong. Eric and Nick went at each other 2/40. I seperated them and they went apart and I figured that was it. I was wrong again. When I returned to the yard Nick was all bloody.
Point being once they were seperated they developed a new pecking order and that was that. Each establishing a dominant attitude. Seems to me Eric grew bigger and he was bigger than Nick after they were seperated.
Since flocks of just hens may have one hen who will take on the roll and characteristics of a roo, even to the point of crowing, it would make sense that two male may develope at a different pace. The smaller male may grow into a bigger roo if the opportunity arises.