I don't have experience in a 320 or 360 but I have flown formation using quadrant, friction lock, and vernier.

The Navion originally had vernier and I found it to be a real pain. I replaced that with a friction lock which is better but I think the movements tend to be large because my hand is hanging out there, pushing and pulling with no support. A setup where you could support your elbow might be different.

The Chipmunk has a quadrant and I love it. I find it's no problem to make the adjustments required for stationkeeping- I adjust the friction so it's easy to move but not loose. I had an experienced instructor in back who asked me if I was adjusting the throttle- he couldn't see any movement. With a good Lead and practice slight pressure was all that was needed- I don't think that would be possible with a standard push/pull installation.

  -Bill Wade