Just some thoughts:

 The wing that you found pictures of is a Mark-I wing.  It has a different design than the Mark-II wing in your kits.  The ply doubler behind the leading edge was edited out of the design/kit because we selected hard balsa for the LE.  That's a lesson learned for me is that with these short kits I cannot rely on my selecting the propper hardness for the LE and not telling you about that.  You can add it in if you like or if you are using softer balsa for the LE.  Softer balsa is fine for the length of the wing LE, but don't go below medium hardness.

 One of the differences in the wings is that the Mark-II airfoil is thinner than the Mark-I airfoil.  The thinner airfoil gave a higher high speed range for the model while the specific airfoil gave a nice low-speed handling.  The Mark-I wing used vertical grain balsa shear webs throughout the wing.  The Mark-II replaces the balsa shear webs with a 1/16" aircraft ply shear web the length of the wing.  When the dihedral brace is glued to the ply shear web you get a compound shear web that runs the length of the wing.  It is lighter and strong than the other design.  Now, if you really want to strengthen the dihedral joint you would need to add thickness to the dihedral brace not length.

 A local pilot once lost control of his Twin-Air .45 due to a bad on board battery pack.  It was fully charged and he went up and 3 minutes later lost control of the airplane.  Unfortunately the plane was inverted and heading toward the pit area.  Nobody was hurt in the subsequent crash when the plane dove and impaled itself into a car tearing the metal on the car.  Fortunately it was his car.  The wing was salvageable after the crash.  It's a tough wing.  I've never seen or heard of one failing in flight.  But like most things, it depends on the builder.

 As for fiberglassing:  2-3 layers of 3/4-oz cloth for 2-3 inches to each side of the joint will alleviate most people's concerns.  I would suggest running the cloth at a 45-degree bias.  Other places people have suggested glass cloth is on the insides of the nacelle sides where it meets the wing and around the fuse in front of the leading edge of the vertical and horizontal stabs (Just be careful not to add too much weight back there).  If you want to go high-tech, use a piece of CF cloth or Kevlar around the LE of the wing at the center section before drilling and installing the dowels.  This will give you more strength that the extra plywood behind the LE.  The stress you are concerned about here occurs in negative-G maneuvers (outside loops and snap-rolls).

 As for the "ply wing bolt block", you know, I was cutting that part all day long and it's still too short.  All I can do is apologize for missing the mis-cut part. Sorry guys.

Take care,
John