The saddle may need so little adjustment that you can ignore it... and just put foam "wing seating" tape on it. The difference in how the wing meets the fuselage will be minimal when taking out the dihedral.

When dealing with a bolt-on wing, its easier to just open up the hole the dowel or peg goes into to allow for the difference. And you are less likely to make the wing sit cocked on the fuselage this way. (This shouldn't be an issue... the Avistar has a rubber band monted wing)