Congratulations, your main cannon rail made me rethink my PDC completely - I had 30kms canons that would get wrecked all the time in instant action mode.
On the other hand your missiles are hot garbage - you will need at lest 50% more DV at any reasonable range. Also even like-for-like-design F-CH4 is 5% free performance over F-RP1 so it makes no sense to use RP1; also having a dual fuel RCS system is unreasonable in the long run.

Still those tiny rails gave me pause, so kudos.