Again, the offending Kitfox does indeed have one mass balance per flaperon.

I eliminated/reduced linkage slop and tightened the shoulder bearing and so far no flutter.

I have not found clearly offending causes of the uncommanded left roll. Flaperon attachments and associated ribs are all firm with no unexpected movement when stressed. The flaperons appear to be at same angle (left compared to right) before and upon full flap deployment - and travel appears to be the same.

Owen