I misunderstood the blue edging thing:
I thought that a blue feather with a blue edge was meant, not a dark edged one.
Lacing = proper lacing
edging = blue prone lacing?
We might have been taking at cross purposes.
Lacing I was meaning as the proper crisp tidy lacing like blue Andalusians. Looks the same as a laced wyandotte.
Edging is what Sigi calls the darker effect that often happens on the edge of a blue feather but does not need Co, Pg-Ml. (or Pg-Ml if that does the same). Is that the same as blue prone lacing?
Also there would be the even blue which is required for blue wyandottes in the UK Standard (but I don't know if it is the same in the Netherlands Standard).