has anyone datamined anything about them ?

from my experience if u make 5 shops in a settlement and 1 shop in another settlement u get the same ammount of money , and for some reason they share the available caps , if i take all the money from a store owner in one settlement and i go to the next one then that one has zero caps also

I have all the different types, just because I like to buy an assortment of crap. It also makes getting caps easier if I need some. I have noticed that store types do tend to share inventory and caps sometimes. I am not sure if having more will generate more caps/day but I think everything else does so shops probably follow the same logic.