There are probably some changes in Falcon BMS since last time you had a look into it. All button mapping and joystick configuration should be made with the launcher; it works the same as in DCS. If you want to map a switch, like the master arm, on a physical switch on the thrustmaster throttle, the ´button_"20"_off´ function in DCS is similar to the ´on push / on release´ option in the BMS button configuration window.
It´s easy to make the button configuration/key mapping the same as in DCS.
For VR OpenXR works best for me. BMS also supports real stereoscopic view in VR, so if it could be set in your VR application for the headset, it is noticable better 3D depth within Falcon BMS.
Best thing is, it runs stutter-free in VR at approx 3800 x 3200 on my PC and looks perfectly fine. Anti Aliasing setting in BMS should be low, like 2x or 4x - the high resolution should smooth out the image.
Anyway, when you got time for the online sessions, we will get you familiar with BMS again. Would be great to have you with us!