I don't know as far as flat more stable but as I said before the sym get higher head speed and that makes it more stable but more damage when you crash. For the flat bottom blades you could just change you pitch curve if you have a DX6,7 or another programable radio. You can try to change it with the linkage but it will mess up the over all pitch (-12 +12 is normal it may be -15, +9). If you do get sym I think you are saposed to use a smaller pinon. (smaller by one tooth I think). Good luck