Im thinking ill be using nearly all of it too. I am considering flanging and spot welding along the straight section of the cut then using the fiberglass filler as 1st coat. Im of the opinion at this point that i can do a better job plus the repair will outlive the rest of the fender anyways. Ill warp and buckle the hell out of it if I try to butt weld it entirely. I will butt weld the edges though. At this point, im more interested in getting to the flare part of the project. Pretty high likelyhood ill be ordering new fenders in the near future unless this 1st one turns our miraculous somehow.I ended up using almost the whole patch but I made a mistake cutting a strip of metal to create a lip and cut back on burn through. I put a little bit of a curve the length of that strip because of the contour of the fender. Net effect was a un-malleable seam. There were a couple imperfections but I could not hammer them out. Ended up removing the strip.