Your right, Most milks no matter what ssp. are notorious for being flighty when small. They do calm down with age. If you are looking for "Pure" ssp. they are out there for both Nelsoni and Sinaloae. I actually work with a pair of each that can be traced back. Nelsoni usually stay around the 36" max mark and sinaloans can and usually reach 45" plus. Sinaloans also have larger red bands, usually averaging 9-16 where as nelsons have 13-18. There is an overlap on the red bands so you can always pick examples that are at either end. They both in my opinion are great animals as with all the other milks and kings. If I had to choose one for a first time milk keeper it will be sinaloan for sure. Good size, calm disposition, and brightly colored. Here's a hold back sinaloae in my collection.