You don't want to go with the bare minimum. Rare birds are notorious for having flaws.
Think about it.
Do you want to be known for selling eggs of birds with flaws or do you want to be known for having flocks that approach the standard in color, size, production etc..
While Appenzellers may be a bit easier, I raise a bird with both a white earlobe, yet lays an extremely dark egg. They also have a carnation comb. If I lose any of those characteristics: white lobe, dark egg, totally black bird, carnation comb, slate legs, horn of ox beak, enough size to be a meat bird, not to mention conformation - do I consider my birds worthy of selling someone some of their eggs?
Unless you get repeatability of standards in your flock and you sell eggs, you're selling crap. That will turn people against the breed.