Hi HH,
So glad to see another WBS breeder!
I don't think I know Mike Smith either but, if he breeds WBS, tell him to pipe in as well. Like many characteristics listed in the SOP there is room for subjectivity and personal preference. Personally I prefer the darker slate legs but not as dark as on some Blacks and Blues I've seen. Sort of hard to describe. I have something in mind but I can't bring it to words right now.
I also would agree with and echo Mike's comments. There are soooooo many things that the WBS need to have improved that leg color would be the last thing I'd be concerned with. In fact, it's so low on my list of priorities that I can't even remember when the leg color on the chicks do finally get their full color. I keep saying every year that I am going to make a week by week photo journal of my chicks but I've yet to do it. Other things take priority.
Speaking of priorities, again I echo Mike. The great thing about chickens is that you can develop your own line with specific traits that have characteristics which can distinguish your birds from others - thus making your line easily identifiable. Each breeder has to establish their own priorities and plan their breeding program accordingly. Perhaps you want a certain leg color to be part of your line. I would suggest looking at your flock as a whole, identifying their strengths and weaknesses, and then deciding how you want your breeding program to progess from there.
God Bless,