I know this is old, but I wanted to comment that I got the RR3.3b2 working with my duet 3d and the flsun qq-s pro.
The z axis trigger height I use this:
G31 P25 X-2 Y-2 Z17.73
The z17.73 needs to be measured but this is what I got on my setup.
Also the diameters I use is this:
M665 R142.45 L280.75 B130 H373.35
M92 X100.63 Y99.48 Z99.3 E392
Now the H373.35 I fine tuned from my homing position slightly instead of 371 as in the robin firmware config.
After I turn printer on I do home the axis, then attach the probe and calibrate 2 times until I get close to 0.01 accuracy. Then I move the printer to start position and use the status page babystep to fine adjust with a paper before print. The probing is done with hotend off and bed on at 60 degrees.