Blades and Gears

I have a Trex 550 V2 FBL setup that is all stock except a HV tail servo, I am running a 2S lipo @7.4v unregulated to power the electronics. I am going to a belt drive for the tail and also want to go to 550mm blades. I would like to try the helical gears and pinion for less noise, so please advise me as to what gears and pinion I can use keep in mind that they must be compatable with part#60078T tail gear drive for the belt setup.
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