Hi Raeldor and all,
So I made some tests with my own setup, here’s how it goes if anyone interested, and maybe it will help clarify the need for “cancelation” 
I don’t own a Brunner yet, but I have a custom-built yoke that deals with the most important “feedback” aspect in my opinion, namely the trim. I don’t get any other force feedback from that yoke, but that’s not a big deal.
Basically it works like a regular yoke, the difference being that the center point can be moved by a motor which is controlled using a custom trim wheel (or buttons on the yoke). That system allows to properly cancel the effort by using the trim, without any direct effect on the pitch unless the yoke is actually moved.
To use this Yoke, I can just let the simulator’s trim alone (at the center position) and just never deal with it. In this case everything is managed inside the yoke and the simulator doesn’t even know about it. The drawback is that there is no visual feedback in the sim (cockpit indicator or control surfaces). To me this is the same thing as hardware mode for the Brunner.
But, one may want to get the physical trim somewhat connected to the logical one in the sim, in order to get this visual feedback or when using the autopilot. To my understanding this is the same thing as software mode for the Brunner.
I implemented that for my Yoke, so the logical trim value in the sim reflects where the hardware trim is in the physical yoke. Which is good for example in VR to get visibility on the trim position.
This is where cancelation is necessary: when I move my trim I want the visual feedback but I dont wan’t MSFS to simulate an action on the elevator (as it has to do with a non-FFB device). Otherwise this is completely unusable: for example if I trim down to release effort without moving the yoke (as in real life), the plane would dive. Which is obviously not the desired effect.
This is where the flight model parameter comes into play. Hope that explanation is a bit clearer
Anyway, for anyone interested I can confirm that setting elevator_trim_limit=0.1 seems to do the job perfectly:
- The trim-related visuals seem to be totally independent, and continue to work correctly
- But the actual effect on the plane (as if the elevator was moved) is suppressed.
Which is great, and I assume it would work the same way with the Brunner.
The drawback is that you have to modify this parameter for every plane. So it would be great if MSFS had an option for that matter, it would be a very simple and effective way to add minimal support for people using FFB devices. I’ll check if this can be modified programmatically using SimConnect, could be a workaround…