More progress. Last week I lifted the tub off the frame so I could address (to steal a line from Macy's web site) "that little bump from a Buick back in 1964". Actually, I have no idea who, what or when it was bumped. But somwhere in the life line between two shades of BRG, there was a bump. And somewhere a little rust creeped in, so I removed the back side, pounded it out and made a new panel to close it back up solid. My welding lessons will start as soon as my neighbor has time to bring over his MIG and get me started. The tub is back down, bolted solid, and I'll start with the floor patches.
BTW I made some very long (8"-10") alignment rods by threading a little of a 5/16" rod. Once the tub is close, the rods can be inserted into the tub and threaded into the outriggers. It makes line-up a snap.