Mine is actually slightly nose heavy at 105mm. When balanced at the recommended 115mm it would need 1-1/2 oz. of weight on the tail and I decided to fly it first and see how it acted. Seems fine the way it is except I need to put a little right thrust in it but, that shouldn't effect the flat spins.

I do have my throws set on "all I can get" and it will roll out if I give it too much input. It may be that I've got more control movement than you and am forcing it into the spin.

I would give you the throws but, the plane isn't here and I won't be able to get to it 'till the weekend. Needless to say that I do have triple rates (low rates per the instructions) set up on it. I am not using any expo in it yet but, I'm going to have to or I'll wear out my rates switch!