Not quite sure you need almost 1000 oz/in of CONSTANT torque on the elevator, one 9380 is almost overkill....
Are you guys using these servo screws? They sure make me feel more confident with these new high powered servos:
View attachment 43719
I prefer deck screws. But all my servos are rated for 1.21 jigawatts.
Yea the cowl is a rather problematic area. I use large rubber washers on both sides. It does help. I plan on laying some extra fiberglass on where the holes are with some metal or thin wood to try and keep the vibrations from egging out the holes. Loctite is a must also.
Oh, Torx drive. It is what separates the men from the boys. especially when the torx slips from the screw and dives into your flesh. very refreshing.