That looks real good - didn't realize with the quick post scan, you were already on top of it with the same kind of concept of applying a backing to the repair instead of just relying on two ends glued together, to hold it (butt end repairs are known to be real weak, metal welding or otherwise. . . (yeah yeah, I know "she said butt end . . he heh he)
I actually used this fiberglass cloth that comes on a roll for seam reinforcement for roofing, worked incredible for that sidecover repair because that puppy was REALLY cracked (I actually ran over it accidentally, in the dark. . .*doh*)