Sanding 125 4.2 m planks is a bit tedious even with a decent random orbit sander but it's still a sight easier than sanding it when it's in place, particularly if it's on the ceiling.
Anyway here's the port side with the inset panels in place:
Whilst the front three panels are square, the stern panel curves both inwards and upwards (from about the porthole) so it is much more difficult to fit. Additionally the top edge is 7/16" shorter than the bottom edge which would have resulted in the plank grooving having a "wedged" last plank if all grooves were parallel.
Dave got round this by "tapering" the back 7 planks by 1/16" each. This is too small to see on each individual plank but results in the last groove appearing parallel to the frame.
It has not yet been fitted yet but the internal stiffening channel sections to the stern of the porthole will also be curved.