breeding plan looks like a winner to me
tho as for adding snakes you have 6 males and 9 females if you are adding a visual pied add a female remember one male can breed several females each season
when I buy snakes I buy powerhouse males and 1-2 gene females (far cheaper that way) and hold back any multi gene females but that's just me
with 6 males you could have 20 females with no breeding problems so any additions made I would add females