Then you're doing it wrong (with all due respect)
For a defense build, MCs suck noodles. You need a high-alpha weapons. You need to strip attacker's shields as quickly as possible and run when they back off to recuperate. If you're just tickling them with MCs, they won't leave you be.
So for a defensive build I'd go with something like pack hounds, beam turrets, Plasma accelerators, etc.
That is something to consider, im using the MC cause i do like them, and for the most part the npcs that ive been getting that i actually go head to head instead of turning away and going out are normally small ships, and with those its normally, fire, fire, shields down, fire, fire, bummm... Done! Bigger guns, with slower fire rate, but especially not that much accuracy vs smaller ships... Somehow seens to me not good idea...
Even npcs with anacondas im having no issue to take them out quick and easily enough, unless they are in a pack i havent had any issues.
Most of the stuff im gonna do, will envolve having to stay in a danger zone to collect something interesting, even doe under fire, so having some offensive capability isnt bad.
Also i need to have in mind the weight of the stuff i need to use better guns, since power consuption in some cases from what ive seen is a problem with only a D-Rated power plant and distributor... Dont know if that changes with engenieering, or if it is visable afterwards to use it as im using to do limited exploration...
Off course that if i go open and end up with a human on the other side... That is a all diferent ballgame...
Its a balancing act, between what i wanna do and what i would like from the ship... Gotta get something that is between.
im gonna stick with this for now, since i do hope i wont even have to deploy them for the most part of the time, but when i take a break to rest from my current "quest" ill probrably experiment a bit.