Mike, the white spotting is much like a co-dominant effect.
The head spot (your gremlin) is the heterozygous form of white spotting.
The white head and white butt ( or Pieds, also what you call Caped and Normal) are just two varying degrees of extreme of the homozygous form of white spotting.
The self (all one color) are the rats that do not have the gene for white spotting.
Breeding two head spotted rats will give you Selfs, head spotted, and pieds.
Breeding two pieds together will give you all pieds.
Breeding a pied to a self will give you all head spots.
Head spotting : Heterozygous for White Spotting
Pied: Homozygous for White Spotting
Self: Normal, no spotting gene
I am interested in seeing the all white one. When you get a chanceIf the eyes are pink, that would be a true albino.
The yellow ones aren't actually albinos, they resemble the Pink eyed dilution of domestic rats.