hi, I just finished my 3rd one, flew it sunday. norvel 25, is hot!
the downflex shouldn't cause a problem.
thread method works, but I prefer continuous covering hinges w/ ultracoat, or ca hinges cut in half (1/2"wide), drill two holes in it and epoxy into wing, c.a. other side into aileron, seal hinge gap; did that on bottom of my new one, as I used the internal aileron link.
watch the stock strut attachment if using anything other than a mild 15. my latest has 1-1/4" 4-40 bolts epoxied into strut slots, heads ground flush w/ sides. use locknut to hold wing on. splitting strut and epoxying a peice of all thread 2-56 through strut was used on last 2, but I think bolt works better.

look at thread titled my 3rd simple ultimate a few weeks back in this forum for rest of mods and tips.

again, mine is wild, knife edge loops, torque rolls, etc. very light with a 25, and a nice cowl, too.