With the increased RPMs of the makita router, my last setting for deep cuts was 6m/min @ 20mm stepdown. I then increased the speed to 120% while cutting, and even that didn’t cause a slightest problem.
But yes I still have to experiment a bit with speed vs depth.
I wonder what your experience is with these couplers for the LR3?
I found several in my junk box and thought they might be useful? They seem to be more rigid than the spring couplers and also probably safer in the situation where you accidentally send your Z too low. The downside is probably that they have more friction to go to their “home” position, not 100% sure if the weight of the gantry would push them down immediately