Resolve of bow in bottom connecting skin - part 2

Previously I deriveted the landing gear bottom cover skin

Resolve bow in bottom connecting skin - We Build Planes

but was undecided what to do with the mismatch.

I cleared the residual misalignment by chuck reaming to 4.1mm using the (outer) bottom cover skin holes as the reference. This would result in a slight elongation of the middle layer (which is the rear skin) and the layer adjacent to the rivet tail (the landing gear box structure). I tried then reriveting, removed the rivet and inspected how well the rivet shft filled the layer immediately under the head (which is the layer of the landing gear bottom skin). Unhappily the "tilt" of the rivet tail due to the hole elongation was sufficient to make just visible a gap between the rivet shaft and the landing skin bottom skin hole edge.

So to remove all doubt I decided to upsize to 4.8mm rivets, enlarging all the relevant holes to 4.9mm. The 3.3mm holes were also enlarged to 4.1mm to take 4mm rivets.

The centre fuselage bottom skin however already had a quite marginal hole centre-to-edge distance of 8mm. Despite efforts to recenter slightly, the enlarged 4.9mm hole centre-to-edge distance dropped below 8mm, typically to 7.6mm.

Since this whole connection is supposed to be load bearing, and given the load is directly perpendicular to the join (unlike some other upsizing scenarios like the rail cone where the main loading is a shear) I decided to create a doubler. This doubler, made from 0.5mm 6061-T6 extended further forward into the landing gear space. The hole centre-to-edge distance was chosen to be 11mm, similar to the improved distance of 10mm chosen for the re-manufactured front bottom skin (the original skin also had a rather marginal distance of 8mm)

This doubler then has a row of 3.3mm holes aft of the main connection which via 3.2mm rivets would attach to the centre fuselage bottom skin, thus providing the additional connection strength by taking some load off the 4.8mm rivets so close to the front edge.