Got my v2 wired and set up according to the guide:

And:
The radio is a th9x modded to have throttle stick centering+the er9x firmware, it has a FrSky DJT module, receiver is a d4r-II set to PPM mode, shouldnt matter but mention it for sake of completeness.
Something which works:
Gear 2pos+Trainer momentary switches are mixed together in a channel as a 3 position.
Either gear pos+momentary pos1 sets the channel in position 2. This position has the MG stop function assigned.
Gear pos1+momentary pos2=channel pos3=fires the cannon, after the reload time has elapsed it will fire again if the the momentary is flicked again.
Gear pos2+momentary pos2=channel pos1=MG start.
Releasing the momentary sends it back to pos1, moving the channel to pos2 which stops the MG.
Snooping confirms and sounds play as expected.
Something which isnt working:
I have one of my switches set as follows, pos 1 engine off, pos2 engine on. Auto start is disabled. The switch needs to be in position 1 for the radio to turn on so the TCB will start with engine off.
When i hook the battery up to the Mega/baldrick TCB it runs the idle sound automatically, which isnt what i have intended.
Snooping the TCB tells that nothing happens when i give driving stick input without changing the switch.
Flipping the switch to pos2 runs the engine startup effect at the same time as the idle is also running and now i can see moving, turning, stopping when giving driving stick input, the engine sound revs as more input is given.
Flipping the switch back to pos1 plays the engine shutdown sound while the idle sound is running and the idle sound stays on, snooping shows there are no driving inputs being accepted and no revving happens.
Anyone know how i can correct the idle to not be on all the time?