I would highly recommend double checking the credibility of your boa being a het for patternless.
The Purple Patternless and Black Patternless are Supers of Colombian and C.A. Motleys. Both are right now priceless, the breeders have kept them.
The Patternless Harliquen, is also priceless. This one is still a mystery.
The Pink Patternless/Scoria is not completely patternless and looks to be recessive (not proven 100%).
The Mocha, has been out of the light for a while, and I don't know what is going on with that one.
If you are looking to make a patternless boa, the best and cheapest way is to buy a pair of Colombian Motleys and breed them together.