For Bf 109 use:
Switch ON = "Mapped key on press": G repeat 2 delay 12000 (m/s).
Switch OFF = "Mapped key on release": G repeat 1 time, delay 0.
Work OK - If you dont surpass the maximum speed for landing gear operation ~190KMH. Above this movement became slow...
Avoid use Alt/Ctrl/Shift+ key in CloD (and in il-2:BoS) send by external keymappers.
BTW - Tom_Perinhon finished the VC for Bf-110.
In game I can not assign action by clicking button №65 (this button is mapped for "G") but in NotePad Clicking button 53 type "G".
Alternativelly, why dont use Mjoy16 toggle positions for Landing Gear: Switch Up send one button (by Mjoy not key from keymapper) example button# 70, Switch Down send other, example button# 60. Mega_Mogz MMJoy firmware have function this too.