I flipped it over and the instructions say to shim the tips 1/16, then shim the rest of the wing.

I'm so confused....

There is leading edge taper (but the trailing edge is straight), but there is also a difference in the thickness of the airfoil from root to tip. If you don't block up the tip as instructions say, you will build in dihedral.
Regards,

Well, that's one kind of taper but the shims address the taper from the root rib vertically to the tip rib, usually measured at the high point which in the Vector is at the spar. The root rib is wider than the tip rib so the spar "tapers" down from the root to the tip. It is important to keep the taper the same, top and bottom, thus the shims.
 The comment 'bout shimming up the rest of the wing just refers to putting additional shims along the wing to minimze any bowing of the spars, ie: a 1/16 shim at the tip would mean about a 1/32' shim at the half way point of the wing. Of course the closer to the tip the shim is placed, the thicker it should be and vice-versa. 

Sorry Paul, I edited that line out and clarified my answer, I hope it helps. Don't abandon ship just yet, it takes building a few planes to get it sort of figured out. One of the best parts of hobby is flying something that you made and that just can't be duplicated by ARF's. Give yourself credit for taking the first step.  You might also get some benefit at the RSM site where Eric posted building guides for a few of his kits. Some good ideas there.

The Stuntwagon wing built "upside down" on the board.  You pinned the spars flat to the board and when the wing was finished, all the taper (in depth) of the ribs came "up" from the bottom to give it a kinda "dihedral".

I think, Paul, that you are just not recognizing that the ribs are not the same "depth" (height) from the root to the tip.  I always centerline the ribs and keep THAT line the same height for each rib from the board.  More sunlight will show under the ribs as you near the tips.

However much difference their is from the rib centerline from Root rib to the Tip Rib is how much shim you need to place under the tip rib to keep the wing centerline uniform.  This does not occur with a constant chord wing.  all the ribs are the same size in length and height.

Example: Constant chord wing= rib that is 9" long and 2" high.  All ribs are the same so no "adjustment" is needed to "shim up" the wing.

               Tapered airfoil wing: Root rib is 9" long by 2" high  and root rib is 8" long and 1 1/2" high.  You have to block (shim) up the tip rib 1/4" right side up and upside down) to keep it level.  The is 1/2" different in the height of the rib, so that is 1/4" each way.

It's actually very simple, you just haven't "seen it" yet.

Big Bear

Paul
      Hang in there mate,the most important thing is to mark a centre line on each rib
and when setting the ribs up if you measure from the centre line to the
building board on each rib it should be the same,eg if R1 measures from the centre line
to the surface of the board  1" ,then R2,R3 etc should be 1" all the way out to the tip rib.
Paul Allen
Australia