Just summarizing some potential problem areas to be aware of and some suggested fixes (refer to this thread's build steps for pics and more details):
1)
DON’T ATTACH THE DOWEL AND MOUNT TO THE MOTOR TUBE UNTIL AFTER YOU’VE ATTACHED THE UPPER NACELLE AND ITS SUPPORT AND THE GUIDE TUBE THAT RUNS THROUGH IT.
That way you can assure it’ll be properly aligned with the guide tube and notch in the wingtip. If it's not, at least you'll have the opportunity to shim or sand the dowel support unit to adjust its height.
2) Also, roll your dowel across a flat surface beforehand to make sure it’s not warped. Mine was and it was a headache I could easily have avoided just by doing this.
3) The marking guide for both the motor tube and main body tube is off. It’s short by about 1/8” and won’t wrap completely around the tubes, so the positions of components will be off. That's because the templates are based on the original Estes 18mm and 24mm body tubes, which are thinner and smaller in diameter than the thicker supplied Semroc tubes.
You can either use the tube marking templates I redrew in post #28, or
make your own by going here:
https://www.apogeerockets.com/Advanced_Construction_Videos/Rocketry_Video_75 for an Apogee Rockets video on how to use Inkscape, Illustrator, or a similar vector program to create it.
The problem may have been corrected by now, but as of last week, the instruction sheet I downloaded that has both marking guides in it was still not correct.
4) Make sure that those little kidney bean inserts that get glued into the Wing Pivot Top don't stick up too high. You may have to sand them down, since they ride in slots in the Wing Pivot Plate and if they're too tall, they'll bind and the wing won't be able to rotate. (See the 2nd and 3rd pics in post #30 to see what I'm referring too).
5) Though not mentioned in the instructions, the wing pivot post is too tall and will need to be sanded down (1st pic, post #45). It's made of aluminum so it sands easily — just be careful not to shorten it too much, which can happen really quickly because of the soft metal.
6) Speaking of the wing pivot post, make sure it's glued in ABSOLUTELY VERTICAL into the Wing Pivot Top. How you assure this is up to your own ingenuity, but if it's even a tiny bit off, you'll be in for a world of problems because it'll tilt your wing, giving it either positive or negative incidence (bad) or result in one side of the wing being lower and one higher.
7) When deployed, the wings will be rotated 6° off perpendicular toward the left side. It seems the holes for the Pivot Stops (the kidney bean-shaped inserts) weren't lasered out directly opposite each other as they should have been (see post #63). I honestly don't know if having obliquely-oriented wings would affect the SWT performance at all, but I don't think it was intentionally designed in, as the original Estes version had wings that were at a right angle to the body. Anyway, see the same post for a solution to the problem.
8) Elevator clearance problem (not enough space for the elevator flap to fit between the
end of the stab and the dowel standoff. See post #70). While not everyone seems to have had this problem, I did and you may. I have no idea why or how it occurs despite repeatedly double-checking all the alignment measurements from the instruction sheet.
The slots in the fins function as a block to limit how far the stuffer/motor tube assembly slides up into the main body tube (and hence, how close the dowel standoff gets to the end of the elevator flap). Seems simple enough, but I discovered that the fin slots were 1/8" too long, and that left insufficient space for the elevator to fit. I'd suggest dry-fitting the fins first to check how much elevator clearance you have before committing to glue. If not enough space, the easiest fix is to mount the fins further forward the small amount needed for the elevator to clear. In my case, it was 1/8”.
Edit
9) If you decide to sand an airfoil into the wing, even if only a modest one, it’s best done
BEFORE installing the Wing Pivot Plate. Once the plate is installed, the wing won’t sit flat on a surface, making it difficult to sand a consistent airfoil into it.
To be continued...