I haven't seen the plans, but it sounds like after elevating the tip (R11) the gap should reduce to 0 at the root. A simple check is to compare the root rib to the tip rib and the difference should be 5/16". That means that the wing is tapering equally on top and bottom as it goes towards the tip. If that's the case, lay the spar on the plans and elevate it as the instructions say. Put a straight edge over the spar, and add shims under it as necessary to keep the spar straight as it goes to the root rib. Good luck.