Steve,
I plan on selecting for yellow skin and willow legs. Since silver spangled varieties such as Spitzhaubens and Hamburgs(both of which the McGraw originates from) have white skin and slate legs, this would further distinguish them.
There is, to my knowledge, one gold spangled McGraw hen in existence. This hen is in the flock my birds are from so I am hoping for a heterozygous silver cockerel.
Thanks,
Ryan