A) re check your measuring... if it is off that far look at shimming the slot in the fuse to help bring everything into alignment, mine was very close.

B/C) I used nylon bolts tapped into the blocks AFTER I added good hard wood to the top and bottom of the installed wing hold down blocks... This was a last resort method short of tearing the blocks out and starting over! on mine the hold down blocks were installed at the wrong angle in relation to the wing... I figured that out AFTER I had drilled the wing and installed the blind nut's I had let let my son and one of his friends bolt down the wing as I went to get a drink... I come back only to find them struggling trying to get the bolts in...yep they cross threaded so bad I had to cut off the heads to remove the wing[:@] only then did i notice the that blind nuts would NEVER work with the way the hold down was installed. I never have been fond of the tapped wood method although it's been used for years, anyway I figured it was the only way to salvage the mess I had made with the least effort so I did. I now have 50-60 flight's using the nylon bolts with no problems.

D) I fly mine with a Magmun 91FS, with my AUW at 9lbs vertical is ok but far from unlimited... it will do anything in the book however and has plenty reserve power for me. I did use the spacer I think you should also. I needed no lead to balance and the cowl fit perfect, servos are in the fuse, if you put them in the tail with a light motor you'll need a TON of lead in the nose.

the only real down side to this plane is the poor covering.
BTW if you like to fly in wind this plane is GREAT for it! I've flown mine in at least 25mph winds... it just loves it

John