Over to Barry:

Various puzzles are now solved as folows: We need the floor in to give the point at which to aim the new inner member base around the new RD inner wing repair. We need to mount the inner sill and use the floor jig to establish the floor position. Once the inner wing repair is screwed into place, the inner member base by the anti-roll bar mounting can be scribed in and tacked. With that in place, that central web can be positioned. With the floor, inner wing repair, central web and ARB mount area all in place, I can make sure that all of the various flanges meet without gaps or stress. I.e., they all lie naturally together with no undue gaps.

It's a classic case of a lot of time going back and forth getting everything re-worked until it all fits and is screwed into place. Then all but the final layer be be removed, the final layer becomes the first layer to be welded in, and the whole area welded layer by layer outwards. The welding itself is probably 10% of the time, if that.

BTW, you'll see the various flanges at the bottom of the featured area hanging well down. These will get trimmed much later on, as will the floor / sill flanges etc. In the meantime it's much better to leave everything ragged, rather than trying to second guess the very final position of everything. Once all finally welded up, it's a simple matter to go round and trim / file everything to the correct dimensions.