Will is right on the plans situation. I know that RCM/E also published plans but compared to the MK plans they are somewhat "blocky". Much of the design makes use of quite substantial block of balsa which are then essentially carved mostly away. The MK design was typically Japanese and used a slightly more sophisticated approach. The trickiest part of a reproduction would be producing a nciely matching canopy/pipe tunnel section which wants to be made of fiberglass to simplify the construction. Matt's original made use of a literal pipe tube made from thin aluminum and a carved balsa top - a hybrid approach which would be quite labor intensive to reproduce.
CAD work would make any approach much easier and lighter in my opinion. I took liberties with the 40 size MK re-design to make it lighter yet - not hard considering that even these wonderful kits were designed 30+ years ago...
As far as I know all plans (and the MK kit) made use of a plug-in type stab. The MK kit came with the required mechanism to be built into the framed up balsa stab.
using foam core surfaces seems like the preferable and easier route today for a good wing and stab. Part of the rear deck (aft third part behind the pipe tunnel) could likely also be made with a balsa skinned foam core but the section is small and just as easy to skin formers with 3/32" (or 2 mm) balsa.
David