I read already about possible more alleles on the cha-locus but with your extra clarifications it start to make more sence to me.
For the "white moorhead owlbeard" what e-allel it should have, I suppose "eb
" even the spangled-tails are "ER" DbPgMl !
I not breed Hamburgs or Owlbeard but Silkies and these "Blue Silver Partridges" should be "eb
" with charcoal. I have it on a young rooster and on a young hen in pure (intending as blackhead).
You can see the Columbian-like restrictors have much more effect on the rooster than on the hen.
When these 2 are crossed I should become +-25% Splash (with all the Silver and Columbian restrictors it should be as good as "white") with keeping the (intense) blackhead !
Is my reasoning correct ?