I've been told that the cockerel carries the colouring and the hens the size, if that helps Roddycm? The genetics of colour is incredibly complex. I started reading notes about it I found on the internet, but just got completely baffled by the whole subject. So good luck is all I can offer you.
Wyandottes have fertility issues. A perfectly smooth rose comb in my recent experience is an indication of potential problems. The breed needs an injection of straight comb periodically I read and this manifests as rippling or bobbling on a rose comb surface.