Just a thought, but instead of cutting your props down th two inches and likely making them imbalances in some respect (if not static lot, then at least from one to the next they likely differ minimally, even if meticulously performed), you might have found success with alternating the motors to be mounted on the frame pointing up and then down for the adjacent motor, thn h next one above he boom, etc... I recently did this for a hex frame I made on which th same 15.6x7 props overlapped minimally when mounted all on same plane. The only way to work it out was to alternate one above--one below--one above--etc. I was uncertain of how it wood perform, but to my delight, it worked really great, and looked awesome as well!!