Wow 15 in one place! That would seem too risky in most of the spots I am thinking of. Maybe your beds are more remote than where I am or perhaps your just in a more rural area in general. Or maybe I'm just a little too much of a sissy when it comes to choosing sites. Sounds like its been working good for you and thats what really matters. Mine are all the exact same 2.5 X 5 feet. Each is intended for 2 girls or 3 unknowns assuming that one will usually get culled and then again it finishes 2. Sometimes I may have 2 or even 3 of these in one local area, but they woould be seperated by 25 - 50 feet.

let me say this, with only one single exception of one single plant, I have never had another one found or stolen. The one single one that was gone I do not even know if it was found or stolen or trampled or what. When I got close enough to realize it was gone I just kept walking and never came back.