Yep just cross the biggest ones and eat the little ones. Don't breed hens that lay eggs that are odd shaped or very small or way too big.
I have 5 roosters and 26 hens at all times and you never hear crowing around my place. They crow because of environmental factors. If they don't have hens...
"Jumbos" were created by patiently crossing coturnix, breeding specifically for size for many generations. As recently as 1960 the average coturnix was 6 ounces. So the size will decrease when you fold in the smaller genes but it's nothing that hasn't been done a zillion times cause that what...
Most hobbyists will not have or build cages large enough to have two roosters get along for life. Double the required space and add extra hens if you plan to try anway