An inherent issue w/ any high ar wing is strength to weight. A longer wing must be more robust towithstand the leverage it imposes on itself. I'm pretty sure a high ar wing must necessarilly be heavier in proportion to the rest of the aircraft to have the same "g" tolerances. One thing that may help is a relatively light fuselage to help decentralize the load along the wing. I've seen Youtubes of dynamic soaring gliders reaching speeds of over 300mph, & pulling who knows how many "g"s in it's d/s maneuvering. Appeared to be high a/r wing & minimized fuselage. Another thing that helps is a high a/r wing produces lift more evenly along its length, because a smaller percentage is losing lift to wtv's.