Whenever Pat deviated from Molt's construction notes, there was good reason. Note the

beautifully built longitudinal hull stiffeners that provide excellent hull skin and floorboard support

on either side of the center-line hull ribs.  This could be part of a textbook on Coot construction.

Less obvious, but equally noteworthy, the longitudinal aileron torque tube has been lowered,

so its aft end emerges below the lower spruce cap on Station 127 (far right beyond this image).  

This allows better alignment of the torque tubes with the wing at the sponson-wing interface,

which, in turn, would give better aileron authority when Pat eventually completes his Coot.