This is one thing which few Commanders consider (well done!), and as yet I know of no good resource which shows the actual Gimbal weapon regions. A similar question arose in
this thread some time last year, in which I stated:
I also linked to EDSY as above, noting that it shows only the hardpoint locations. For the moment, you will need to watch the deployment directions and whether parts of the starship might obstruct the weapon. Obstruction can be even a problem for Fixed weapons; for example, the Fer-de-Lance landing gear blocks its class 4 hardpoint from using a Laser or a Cannon, which can make it poor for gear-boosting.
As I stated before, the Fer-de-Lance is also a great example of poor hardpoint arcs, and something like the Krait 2 is not much better given that its class 2 hardpoints deploy downwards. Conversely, the Mamba hardpoints
all deploy upwards, such that their arcs can all strike a Power Plant at point-blank range despite the wings having undesirable separation. A very effective use of a Chieftain can be to place Pack-hound missiles (generally, Seeker missiles) in its lower class 2 hardpoint, because its other five are all atop, all deploy upwards and are all very close together.