Ok, IMO it has nothing to do with your setup. Although I personally like to see a little better mechanical advantage in the arms then 1:1 that you essentially have, the 7955 should handle it just fine. I see that you have sealed the hinge line as well. We can rule out your setup. The next thing is to inspect the stabs and elevators for any damage. You most likely did that already. Check for any play in the stab tube/socket. As I said earlier, not very common to survive flutter. When it happens it’s a very distinctive sound that is hard to mistake for anything else. If you don’t recall hearing anything and your stabs install onto the fuselage without play then IMO you are good to go.