Get your center line layed out on the stave. I go by eye...getting my glasses on with the light right and closely following that linear grain full length of the stave. Decide where you want your bow to rest on the stave, and mark the center of the bow on the centerline you've drawn. Lay out your handle and fade area. If you're going to put snake skins on, I usaully opt for the same limb width to midlimb and then start your taper. I usually start off with the tips at 1/2" and narrow them later. I mark lines across the limb every 2" from midlimb to the tips. These lines should be close to 90 degrees off the centerline...with a snakey bow, that may mean all these lines don't look like they're parallel with each other because they're rotating with the curves. If your limb width is 1-1/2" for example at midlimb, along the first 2" line measure out from the centerline on each side dropping maybe a 1/16". Do it in your head first working down the limb for each 2" increment and you want it to end up at your 1/4" for each side at the tips (1/2" tips). If 1/16" increments work out...first marks either side of centerline on your 90 degree line would be 11/16" for each side, next...5/8", next..9/16", next...1/2" and so on. Connect the lines by eye trying to keep it curvey!