1200mm Dragonfly

I started at some time around 1956 - when the town's newsagen began selling little four piece balsa chuck-gliders that you had to slot in the tailplane, fin, and wing, then fiddle about with a little lead weight that clipped on, to get the balance right A bit later, I advanced onto similarly constructed rubber powered models, called Sleek Streek (the trivia that we remember!) for about 1 shilling and six pence. (about 12p now!). That taught me about trim, balance, and thermals! Several of us used to fly these little toys in a disused sand-pit at the end of the street. I now know it was an excellent sun trap, and that hot air rises! (taking your little balsa model with it!) We chased those little things al over the estate, hunting in front and back gardens, looking where they had got to!

I posted a reply that seems t have vanished!
I put - - I'd make the braces longer AND tapered, to form a triangle box. That would spread out the load stresses, rather than concentrate them in one place.

No, matey!
You do like trying to re-invent the wheel!
Ailerons - TOP-hinge, always - so the fast-moving air over the top isn't disturbed.
For a Flap, you can have a bottom hinge, because in the raised position, you have clean air over the top, but when lowered you get turbulence, which equals drag, over the gap, and you want the drag to slow the wing down!

For your wing-joiner, you have got the taper the wrong way, although you can reduce the thickness as well, if you wish. 
BUT you need to avoid vertical stress-lines that all line up, because that becomes a weak point where the structure will fail.

 
 

One of my self-imposed rules when building  (especially old) kits is to NOT blindly follow the same mistakes the original designer made!  
I llok at the drawing, and if I see something that looks a bit 'off', I think -"How would I do that?". or "What was it trying to achieve?"

Round here, they used Mersey Flats for transport.

FF models always had way too much dihedral to ensure stability and a fast return to level flight, a beginner should have some, say 3 degrees but most aerobats have none at all, the roll axis has to be controlled all the time, I'm told it's something you get used to, I haven't yet.

Having re-read the above, a high wing model needs very little at all.

Rake and Dihedral are different things.
Dihedral is the amount the wing-tips are raised above the section at the root, with the root on a flat surface - when looking from the front or side..
Rake - can also be called sweep, Looking in the plan view (from above) is the amount the leading edge is swept forwards or back with reference to the root ribs.
You can have Rake (or sweep) with NO dihedral (there are other aerodynamic considerations too) and you can have Dihedral with no rake.