The tack welds for the bend, hinge, and closure are in. It's time for a test fit.
Not too bad, not perfect. I started the half-inch-radius bend in the front just a smidge too far up the hatch so there's a 1/16" or so mismatch backward and up.
Also, I had a little trouble with one of the tack welds for the right hinge fitting. It's angled up slightly to put the pin at the right height, so it's not actually sitting flat against the 22ga steel the hatch is made of. The not-quite-a-lap-weld Just Would Not Bridge.
Cranking the amps up to somewhere between Righteous Fury and Raining Hellfire did the trick, but thank goodness for the aluminum chill strip or I'd have punched a dime size hole right through. As it is, it's nothing a grinder can't fix.
I think I'm going with this. It's not like the OEM enclosure is exactly precision manufacture either.