Black flag works well...and quickly.
The brown widows are the males. Poor fellows..... they are not as big as the females and they don't tend to bite people.
All spiders are venomous. It's just that most spider's fangs are not long enough or strong enough to get through the human skin. Of those that can, only 3 (?) have venom that is particularly dangerous to humans. Tarantula, Black Widow, Brown Recluse. Many times a BW bite is not a big deal.... not that you want to get bitten to find out. depending on the amount of venom and the person's tolerance to it.
Bat... several of the BW's around here have been pretty big. Of course.... it's like a fish story too... they tend to get bigger every time the story gets told.
So far this year... I have only found one on my property. Black flag solved it.