V912 main roto blades

My new toy is the V912 from WLToys. A nice 4 axis RC helicopter 40cm main rotor diameter fixed pitch.
I looked for the best way to print blades (I don't yet break one but the question is not "if" but "when" I'll break one!)

There is here 3 versions of blade:
the original is almost the same of original one ;)
the two other are some research for more "silent" blade.
The small one need more rotor speed => more stability with the bell bar (gyroscopic effect) => less flight time because o