10-15 not uncommon here. Bachelor colonies under sheds or wood foundation farm houses.
Spring time maternal colonies up to 6 females with kits if the space permits.
This fascinates me. It shows how different animals can act, area to area.
In my area, striped skunks are usually solitary. Females will winter together with possibly one male present. Males are solitary year round. They do not tolerate each other. There are no bachelor colonies here in my experience. There are no maternal colonies. Our skunks spray if another skunk shows up at an occupied den.
As to the OP question, my record is twelve females from one den in November.