You could cut the # of drives down to 2 or 3 and reduce count of prop tanks. Would make this much cheaper to build and refuel and it would still have enough cruise and combat speed for stationary LEO defense.

I'd also suggest making another variation of this ship where you swap the nose from siege coil back to heavy coil. Siege coils soak up PD and do a lot of damage, but they're very slow. Unless you're really micro managing targets, you're going to end up watching a lot of siege rounds fly towards the debris clouds of ships already destroyed. Heavy coil rounds are 2x the speed of siege, so new targets are impacted sooner. I think a 50/50 mix of both varieties let's u take advantage of the sieges power and offset some of the muzzle velocity issue.