I would prefer it inside, but it mainly depends upon the layout of your theatre. One important thing you could do is maximize the use of your employees. What I mean by this is can your box office and concession stand be somewhat connected, so on slow nights the box office person could also very easily double as a concession attendant or easily help in concessions when needed? The first theatre I managed was a single screen, that made great use of this. People entered the front doors, directly to the box office, then proceeded to the concession stand which was along the same wall, so the ticket seller could help in concessions in 2 seconds if needed. In the project I'm working on for myself, my lobby is very small, and figuring out the best use of space for box office and concessions is important, as well as effectively using a minimal amount of employees. One thing you could do is look at what other people have done. Go to cinematour.com they have thousands of theatres listed with thousands of exterior and interior photos. I've gotten a lot of great ideas just by seeing what other people have done, both in my geographic area and out of it.