I have followed this thread with interest because I have been running the CN12-RXC motor with the 3020 prop for two or more months. I didn't break in the first motor and it didn't last as long, but it still lasted at least a month. I broke the second one in and it is still going strong. I don't do 3D, yet, but it holds strong on full throttle climb outs and decents. It is mounted in the stock t. motor holder. I used a dremel to round out the flat side and put CA on the outside to beef it up. The letters on the prop are facing the motor (faces the left as viewed from the rear).
I DO use the G90 gyro and it's switch is in the reverse position. I also use a GWS esc. To my knowledge, this is the setup both Kyle Stacey and John Adams use. Kyle may use a different prop., I don't remember for sure.
I tried to find out in another forum whether there were any physical differences in the CN12-RXC and the CN12-RLC that we could actually see. Here is the link, but I don't know how reliable this member is, although he seems to be regarded as an authority. He also uses "GWS" in his name.
One possibility, I suppose, is that those of us that have had success are using the G90 servo with the "reverse" switch on, but the motor connected with the correct polarity. I just realized that another difference may be the use of the separate esc instead of the stock 3n1.
One other note. If the stock motor runs in the opposite direction from the CN12-RXC, remember that the stock motor is geared, therefore reversing the direction the prop spins. ACTUALLY, lol, I just compared the stock prop to the 3020 and they have opposite pitch, so the motors MUST turn the same direction. The effective difference is that my tail rotor is turning clockwise as viewed from the right and the stock tail rotor turns counter-clockwise as viewed from the right. I know that aerodynamically this is not proper, but Hey, it works!
I hope this helps someone, as I really like the DD t. motor. I had hoped to get a more definitive answer on identifying the two motors. Maybe someone else will post an answer.