To prevent glue getting through the fabric, you might want to first spray on the back (2 adjacent sides), smooth those sides. Next staple those sides (on the back as well) and then do the other 2 adjacent sides in the same manner.
Don't stretch the fabric too much - whatever method you use - since stretching the fabric unevenly will change the percieved coloring of the edges more, due to the way light reflects on it.
good tip. I was actually planning to wrap the individual pieces then assemble them with metal corner brackets. I thought I recall seeing a post about doing it that way. I'm a little worried about butting the miters together that have fabric wrapped around them but we will see how it goes I guess. I figure with some clamps I can get the joint pretty tight and use my air nailer to tack them in place.
By the way, if anyone has allot of stapling to do, I bought a pretty cheap pneumatic stapler --was around $30 and it works like a charm!! It's like I'm hunting for things to staple