I've been going by pattern primarily - choosing the ones of the right sex who have the most half bands. I've just started as a breeder though, but a banded cal king without any complete bands is something I want.
Once my corn breeding starts, color and clean pattern is what I'll be after.
Another consideration is feeding. Unless it is spectacular, try to avoid the poor feeders.
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11.14 L. getula californiae (Cal. King)
2.3 L. getula nigrita (MBK)
1.0 L. getula floridana (Brooksi)
1.1 Pantherophis guttatus guttatus (Corn)
0.1 Pituophis catenifer catenifer (Pacific gopher)
0.1 Heterodon nasicus nasicus (W Hognose)
4.2.14 Elgaria multicarinata multicarinata - (Cal. Alligator Lizard)