I would not gamble on two 66% hets, you turn your chance of success way down when you are dealing with two unknonws. By they time you figure out if both snakes have the gene and if they do also get lucky enough that they produce (only a 25% chance of that even if they are both het) by that time the price will have come down due to people just outright breeding Black Ax to Black Ax. Throw another gene into your mix of 66% hets and you might have to produce *hundreds* of snakes before you get what you want assuming you ever do since you're not starting out 100% sure that you're even working with the gene.