Hi Sim;
It sounds like you're heading towards a storefront.
I would say that you can do what you're thinking about but I'd urge you to put in some risers even if they're only 6" inches.
Our Dreamland theatre has a flat floor section and we now wish we'd sloped it. For some plywood and 2 X 8's you add a lot of comfort.
The staggering is absolutely important as we had some seats even with a small riser on the back side and even still we had people who complained about visuals. We staggered the seats: end of problem.
I've got a plan of mine own for a small in town theatre and it uses a one person to run it format and some risers, etc. all in a small storefront.
Downtown associations really want and try to get theatres because they generate traffic.
Mike Hurley
www.bigscreenbiz.com