How Big Should a Stage Be?

[Juniper]

Help me out, guys -- I know we have some musicians here, so surely someone knows the answer to this. I need it for a story I'm writing.

Say you had a little nightclub/bar, and you wanted to build a stage for bands to perform upon. How high would you make it (I'm thinking about 3'--it's in an old house with high ceilings), and more importantly, how big should it be? Say you don't have a lot of room 'cause it's a fairly small space and it's going to be tucked into a corner, so we're talking minimum reasonable area.

And if my character should say "you'll need to allow at least X square feet for a drum set," what would that X be?

Also, what other design considerations would you suggest?

Thanks bunches!