Yes, the dished viewport! Just ignore that... if you don't then you realize the gunner's can't see much at all... not that visual targeting even makes much sense given the speeds & distances involved - plus the darkness of space!
For my rationalized MF build, the gunner's viewport will only be used as an emergency backup for the holographic targeting system and will be a simple protruding bubble for the head. The guns will mount vertically in the center of the current 'window', so they have a full range of motion and can 'close' the gap in the rearward fields of fire. The turret disks will rotate. The gunner's stations will be internal pressure vessels aka 'globes' that allow a full 360-degree view of the near space around the ship (think 'Last Starfighter'), using the aforementioned holographic projection system. All this is tech that was demo'ed in ANH, if done using somewhat less 'slick' SFX than is now possible. Even the idea of automatic gun operation is allowed (actually preferred again because of the speeds, etc.) since the ship has a 'brain' - so why not the weapons system too? So gun system modes could be with one or two gunners at the stations, or remote control using what would essentially be a visor mounted system or full automatic - are all within the 'envelope' of the SW universe. Basically, gunners would be tasked with target designation, not engagement since it would be beyond most 'organic' operators to do so in "space combat". Various degraded modes would also be available, resorting to manual control as automatic systems fail or are damaged. Sort of the 'last hope' situation.
Oops! Waay off topic.. sorry! Yes, rotating turret disks!
R/ Robert