craftgrrl | (no subject)

I have a question about reupholsteringreupholstering some couches.. nothing fancy, a somewhat functional but luxurious fabric. It will be going over a comfortable canvas material couch with curved arms, and will be my first attempt.

Does anyone have any pointers for me? I'll be using a heavy duty staple gun.. what size should I use? How much extra fabric should I allow to work with and how do I handle a couch that has piping.. take it off?

Thanks for your help :D