I've not been on for a while, so great to see the fantastic progress on this. It's going to be fantastic!
Thanks also for the reference pictures of the sills. It always amazes me how random the original welds were. Also I'd love to know how they do the outer sill lower spot welds, as obviously you can't get in behind.
I use the single sided gun in the big spot welder, but only for cosmetic purposes, the structural welds being MIG plug at this point (single sided aren't for structural welds but perfect for wiring tabs, captive nuts and cosmetic weld-a-likes that might, possibly, add a little extra stiffness).
Wamer weather on the way, much nicer to work on your car(s)

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