The only advise I could give him on improving rose combs....when picking your breeders try to keep pullets that dont have a rough comb on top...smooth as possible. On the cockerels try to pick a bird that has a good spike and narrow comb....dont use a bird that looks like he has a tomato on top of his head...its a long process and will take generations to get the comb looking good. I always hate the combs that look like someone pressed their thumb down on top of the comb and left an impression.
I would raise as many chicks as possible...as long as you have room to grow them out, its a numbers game when you are trying to improve the combs, so the more shots you have at it, the more likely you might hit your target one or two times.
I wouldnt get obsessed with the combs to the point that I was culling birds with great type because their comb wasnt perfect...you dont want to throw the baby out with the bath water.
Jerry