Right hand sill with worst corrosion seemed to have most of the rot in centre section, I think the front section after cleaning up was actually OK apart from a few pin holes , however seemed quite solid around these however will get a second opinion. May require a small patch, plan to take the front wing off on that side to also inspect a little further. Sorry cannot get to it at the moment for a better picture.Are you just planning on doing the mid section panel replacement? The front bit that you cleaned up didn't look too great in one of the earlier photos (it may just have been the photo though) - would it not be worth replacing that as well while you're getting the mid section done?
Also on this side I just wire brushed down front and rear sections and only temp applied some Hydrate 80 . The blue tape 1.5cm wide was left on so that hydrate 80 did not go on areas that may need welding, although I suspect only surface is converted and any metal underneath can be got to.
At rear you will the tape is just in front of the mid to rear seam.(panel overlap) I would suspect the repair panel will be pushed forward a bit possibly from just under the rubber bung in picture. The total length of the repair panel is a bit longer than the centre section about 3cm from memory from widest area of overlap if that makes any sense.
I will get some advice when repair being carried out, as obviously only want to do this once!