Check the wing tips of your edge for a possible twist. I really think the other guys are right, though. You are carrying to much weight for this airplane, with a probable rear c/g by adding aft weight to offset the engine nose weight.
If you reduce the overall weight of the plane and use a smaller engine appropriate for tat weight, you will likely see an overall increase in performance and improved landing habits.
I've flown the Lanier 25% edge with the c/g 6 inches behind the leading edge instead of the suggested 4 3/4" and the plane landed VERY slow and there was no tip stall/snap characteristics
noted. The plane was powered with an MDS 1.48 and performed exceptionally well. KEEP IT LIGHT!!