Spent the day whittling on the floor. The kick-up in front aligns with the cowl and the floor extends to the back and the sides. On one side, there's a six inch long gap of about 3/16 of an inch; otherwise, the gaps are 1/16 or less.
I finished fitting and tacking the four C-channels in place on the bottom of the new floor. It's already considerably stiffer, but not yet ready for any weight. I've braced the floor with a piece of angle iron to hold it flat while I work on the channels.
This week, I finished the welds on the drive shaft tunnel hoops. I cut a few inches from the too long floor to use a a template for fitting the C-channels to the floor and took advantage of the opportunity to see how the flooring might be bent to form the kick-up transition from the floor to the firewall. The experiment with partially cutting the floor and bending the uncut part was successful. I trimmed the C-channel to match the profile of the floor and tacked the first of four pieces in place.