All "strains" (or morphs) are the same personality-wise, temperment and attitude is dependant on individual snakes, but if you're doing it for fun, start with the pair or normals you've got now, and if you like, then start to amass some nice, lower-end morphs. Seeing as how you are new to breeding BP's, if you're truly serious about it, go to
www.ballpython.com and purchase the Ball Python Breeding Manual by Dr. Mark Seward feat. the Sutherlands. It will answer all 14.3 million questions you have as a first-time breeder, and many more.