[Contracts] Painting a Mural in a Restaurant - Advice needed!

Im new to this be gentle plz<3 Specifically, if I'm in talks with a restaurant owner who's interested in an indoor mural, but is open every day, would it be better to paint at night? Would asking for the lights to be left on after close be a dealbreaker, and should I be concerned about doors being left open while painting? I'm not sure how much electric bills run in a small restaurant, and if I'm painting during the day I highly doubt customers would appreciate paint fumes with their pizza. I'm beginning to think asking them to close shop for a couple days would be the best option, but I'm not confident that's something a client would be ok with.

Any advice helps, especially if you've painted an indoor mural at a restaurant before!