is there someone out there who has experience with a sublease to a ca non-profit of space for art instruction?

Mary Ann,
You didn't specify your exact location (city). Regardless, I think you're better off hiring a commercial real estate broker who has access to commercial sublease contracts and who can prepare it for you. You can hire him/her as a consultant for a set fee (Don't hire a residential agent...big mistake..they just don't know). Commercial sublease contracts aren't easy to find by non-real estate professionals. I doubt if you can find it at a stationary store. The sublease agreement has many aspects that must reference the master lease and detail the obligations of the lessor, lessee, and subleasee.