I would spend some time on world of ball pythons big list (warning can be simultaneously frustrating and addictive) look at the combos with morphs your interested in and use that to guide your pickups. Other advice is since you already have 2 males then get some girls! They are the foundation of any breeding program regardless of species. Gotta have the ladies and they will take the longest to get to breeding size/ age. Most females take 2.5 - 3 years at least while a male can be producing viable sperm before 6 months. One male can breed 10+ females a year, and I'm willing to bet a few scaleless hets bred a lot more than that last season.