RE: FP heloCP blades on FP helo
In the mid 80's I had a Cricket, too. No gyro, wasn't easy to fly [8D]
Some of the PE flat bottom blades (slight pitch curve) come with plastic cams that you glue over the mounting holes (I use dbl sided tape) to add pitch and set tracking. Your idea should work fine if the blades are long enough (but don't hit the tail rotor), light enough and you can achieve head speed. Make sure the tracking is dead on.
I would like to see a picture of your straps.