Another beginner question, the manual has the wing sweep adjustment through moving the forward spar attachment. Wings are on the plane with clamps. Seems that the sweep can be adjusted merely by rotating the wings a bit and the forward spar location at the carry through tube is not fixed anyway. If I bring the spars all the way forward and hold with straps, the sweep is not adjusted by moving the brackets? Voodoo! Am I missing something obvious? Been fretting this step for days.