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