I'm doing a similar project currently, however its not very focused and I'm working with a bunch of breeds. I have a buff Brahma roo, rir, and eiher new Hampshire or freedom ranger roos over my hens right now. And I'm working with about 8 different hen breeds. My light Brahma before had improved size for sure. I got heavier and larger leghorns and easter eggers. But now I'm more loosely creating a barnyard dual purpose with random colors (which is really exciting for me). Its not the main project I want to do but for production, its one we do to help fit those needs. I do recommend using a good quality BrahmaMy main breeding project for the year is to cross different heavy-breed chickens until I come up with a nice dual purpose bird that is: a good forager, good layer, good meat bird, interesting feather patterns, and calm mannered.