From another post of mine in the past:
You will want to get a 12" clearance strap duplicator. This will let you accurately drill a rivet hole in new belly skin or banana wrap, so that the hole is located over the underlying hole in frame or skin that you want to rivet together. Go to http://www.aircraft-tool.com/ecatalog.htm
and see .... darn, there's no page number. It's and Adobe Acrobat document. Click the binocular 'search' icon and enter: 62-12 -- You do want the strap duplicator for #30 twist drills since this is what you'll use most often (just ream out afterward with a #21 drill if setting a 5/32" rivet). This is the handiest tool ever and you can thank Forums member markdoane from Minnetonka for the idea.
Snipping metal shears (you won't want scissor type metal shears from the hardware store!). In the http://www.aircraft-tool.com/ecatalog.htm
catalog again, search on: Jilson Supersnip -- I haven't needed a 2nd blade by any means -- the original is enough. I also don't know enough to recommend the cheaper one on the same page. These shears are time consuming but reasonable unless you have air tools already. I would use a hand tool like this for such a small job (ie, a single trailer). You won't be asking "why not" on tin snips after you see the undistorted smooth edge these produce! Good tools make good trailers/aircraft!!