RE: OS 120 AX, 3D?
I had the 91 fx int eh UCD 60. Truly, plenty of power. Hover pullout was very strong. I think the 120 ax ould be overkill in this [lane, but if you want one engine to use now and for the funtana later it would work. Just be really careful with throttle management. NEVER use full throttle in level flight.