As reported by other builders, there is a poor fit between the predrilled #30 holes in the aft end to the lower side skin stringer. The last 9 holes misalign by a full hole diameter. This was easy to fix however, I over bent the stringer flange with a pair of pliers enough to get the clecos engaged in their holes, then used a deep C clamp to force the skin flange of the stringer progressively down to flush with the skin and against the aft fittings. Then I bent the upstanding leg of the stringer back to vertical.