I cut the flair with a dremmel cut off tool. I cut about 8" at a time and the outer skin would line up then Mig weld a little as I go. After it was all tack welded then finished closing the gap. Nice and slow so it doesn't get hot or warp. Slowly grind it down.
Threw some acid etch primer over the left side, still more to do before the rest of it but the metal is now even across the fenders:
Overlap:

Cut and welded flush:

Getting there, more to gind:
