300 and under opens the door to quite a lot.

you could get a lemonblast (pinstripe + pastel) and a bee (spider + pastel) for, if you go to reptile expos and keep yourself informed, each under 300.

that gives you chances for stuff like spinner blast (spider pinstripe pastel), killer bee (super pastel + spider), killer blast (super pastel + pinstripe), and the jackpot would be the 4-hit killer spinner (super pastel + pinstripe + spider). And also chances for more bees, more lemonblasts, and super pastels. Chances to produce a normal would be 1 in 16, just as low as the chances of hitting the jackpot, the killer spinner.

its just one example, for 300 maximum per ball python you have a lot of options. I mean, a lot of two-gene options. i just picked the most obvious ones, that would lead to a nice and diverse clutch if you have a success with breeding. there are other options as well.