What? Are you SUPPOSED to leave the leading edges of the fins blunt and square? I got the palm orbital sander away from the wife and feathered my edges to a more knife's blade leading edge. Did I do wrong? I haven't found any D12-3 or D12-5 to give it a maiden voyage yet.
No! You did it right. Only lazy bums like myself leave them square and paper the surfaces. Maybe the top 1% will roll their eyes at the square edges, noting they are the bane of the hobby, but the rest of us slackers don't seem to care much and just start digging for a bigger motor to cover up our inadequacy. With good aerodynamics and light & strong construction you might even deploy at apogee on a D12 5! Slice through the air like a knife. Nice and quick your skeeter is!