Great info Ermeio!
You will note though that the version of the Ca.20 that I'm building is slightly different to the patent drawings; the arrangement is slightly different and there is no gunsight visible in the contemporary pictures. Those pictures indicate the trigger mechanism was positioned inside the cockpit itself, at the end of a long tube.


Later modifications to the aircraft, however, may have had a different setup.
To my mind, there still must have been some kind of cable to the trigger, so i'll be modelling something like that (even if perhaps not entirely accurate).
Cheers,
BC