You can get away with 96" x 44" capsule shape. which should give you 242" of perimeter, or 22" per person with 11 people (10+dealer). The felt area will be smaller depending on the width of the rail you want. I'd recommend 5" rail so playable area will be 86" x 34". This is reasonable so your dedicated dealer doesn't really have to pitch cards more than about 3 feet. You can set your betting line however you'd like - some prefer about 6"-8" or so from the felt perimeter so the can keep their cards near and still be able to stack chips 2-3 deep in front of them.
Of course, if you decide to go a bit bigger, then it gets people a little more comfortable.