Does anyone have any suggestions and how to find trustworthy photographers to share the space with me?
There's a couple options: have tenants sign a lease or rent-as-needed. With the former, you'd receive rent for the lease term. I'd call other studios and freelance assistants to see if they know anyone looking to hang a shingle. The latter solution requires babysitting. As an ex-studio manager, I was the guy who stayed at the studio to make sure gear worked, toilets flushed and, most importantly, make sure the place was returned to the agreed upon state (which meant making sure the client repainted the cyclorama to white). For this type of client, perhaps shops like Samy's Camera know where their clients find day-use studios.
I would ask my insurance agent about both those scenarios and see what they say. One might have a cheaper premium than the other.
