It would be nice if yall could introduce some columbian brahmas like light or buff from a show breeder to try to bring up size while maintaining color and egg production. Maybe take a couple hens and put them with a nice show rooster then take the best overall birds from that (type, color, size, egg production) and mate those back to a show bird one more time. After that breed those bigger birds into your flock and you should be set, It would speed it up a couple generations as far as type.