My fleet is primarily missile focused
Combat Ship classes:
6,000 Tons: Frigate - Operate in groups of 2
12,000 Tons: Destroyer - Operate in Destroyer Squadrons (DesRon) of 3x Destroyer, 1x Jump Destroyer
24,000 Tons: Cruiser - Operate in Cruiser Squadrons (CruRon) of 3x Cruiser, 1x Jump Cruiser
48,000 Tons: Battleship/Battlecruiser - Operate in Battle Squadrons (BatRon) of 3x Battleship, 1x Jump Carrier, or 3x Battlecruiser, 1x Jump Battlecruiser
This may be a personal taste thing, but once you get up to capital ship sizes I would just abandon the idea of jump warships and use tenders, either commercial (if low speed is okay) or a smaller "warship" class with minimal armaments mainly for PD. At that size, you're paying a lot to build something that's not carrying its weight in a battle situation, to the point where you're better off using the resources and shipyard time on something more capable. You still need the jump drive but a smaller ship dedicated only to carrying it will still get you where you need to go for a minimal investment.
For the smaller classes while this is still technically true, if you intend for those ships to operate in small groups independently then having even basic PD guns on the jump ship is worthwhile. Capital ships however should never be operating independently without a supporting fleet so this logic doesn't hold.
General fleet comments: Speed mostly looks good for IntCF, assuming the frigates are not intended to be fleet units in most circumstances the speed mismatch is not a problem. Some people will say you need to be faster but for a missile fleet 7500 km/s is fine and you have 9000 km/s on the beam BCs so I see no problems. Engine/Fuel ratios look fairly close to 3:1 edging higher which I think is good for a combat fleet as long as you can manage the fuel logistics. 30b km range is in my opinion a good target for a fleet. Maint lives mostly look good.
My main issue is that I don't understand the use of shields here. Each shield you have is nominally equal to one layer of armor which IMO is not really enough to gain the benefits of shields - I've seen NPRs at lower tech levels than this deploying
much thicker shield layers at their relative ship sizes, probably about doubly thick on a per-ton basis. With such minimal shields you're not absorbing enough damage to really blunt weapon penetration or absorb enough damage that your hull doesn't need repairs after a skirmish, which are the major advantages of shields. They're just going to be broken too quickly to accomplish anything particularly impressive.
As a secondary issue, I would strongly suggest that at least one fleet class carry passive sensors in the size 6, 9, or 12 range, especially EM as this will let you outrange all possible enemy active sensors at equal, +1, and +2 tech levels respectively. Size 3 doesn't really give you that benefit although in practice it will probably be fine.
Spruance C class Frigate 6 000 tonsLooks suitable for the mission profile, though I think it's over-armored. I don't like the armament as 25 cm railguns are too heavy to be a good dual-purpose armament and for light anti-ship armament I'd rather use lasers for the range. Your BFC needs a longer range as it will currently have 0% accuracy at the maximum range of your weapons which compounds the already short-range weakness of railguns. Generally with BFCs there is little reason to have anything less than 4x range multiplier unless you are seriously starved for tonnage or designing a PD-only BFC in which case a range of ~100,000 km is adequate to get 90% accuracy or so. Finally, I'd reduce the active sensor size/range and bump up the passives, extra active range isn't helpful on a beam ship and if you want to tail/monitor/scout passives usually will do what you need anyways.
Outreach C class Destroyer 12 000 tonsNelson C class Jump Destroyer 12 000 tonsThese railguns are better as DP weapons, though the fire control is a bit weak still it is fine for PD work. I think the AMMs should be faster at IntCF tech but they should be able to outrace any comparable-tech ASMs which is the important thing. They will struggle against NPR AMM spam I think. The RES10 sensor isn't really needed since, again, you can't really shoot at anything beyond the range of your RES1 anyways. I personally would mount 2x BFCs for redundancy (even on the frigate if space permits, actually).
Sword C class Cruiser 24 000 tonsI'm not sure why you've chosen to develop both Gauss and Railguns, but this is a fleet threat not a tech thread so okay. I might have preferred 30% launchers to maximize salvo size (assuming you don't want box launchers for any number of reasons). Triple set of active sensors looks sensible. These should have a CIC or the jump cruiser should not, IMO, keep it consistent.
Shield C class Jump Cruiser 24 000 tonsThe RES10 active sensor is a complete waste of space.
Revenge class Battlecruiser 48 000 tonsThis ship is going to die horribly in deep space. On one hand, you've got them set up for 9000 km/s speed which should indicate that they are intended to operate independently of the rest of the fleet (7500 km/s) - not IMO a good use of capital ships, but it is a valid battlecruiser doctrine so okay. However, these have zero point defense and will be easily torn to shreds by any missile fleet of appreciable mass. If you see this and decide to instead escort them with some destroyers, you're wasting 1/6 of your engine power/mass and forcing your destroyers to engage in combat at beam range where they are woefully unsuited.
Rampage class Battlecruiser 48 000 tonsTechnically if these are intended to operate independently (as a BC squadron rather than a full fleet, of course), a jump BC is okay but you want to dedicate the remaining weapon tonnage to defensive weapons, and a reduced particle lance armament is not that. I would also put a flag bridge here if they are intended to operate independently.
Newport class Support Vessel 36 000 tonsArgentina class Fast Tanker 36 000 tonsCalico class Collier 36 000 tonsPersonally, I would say that if you're going to use boosted engines on your support ships, you might as well go all the way and match your fleet design speed, especially since you should be relying on commercial ships for your day-to-day fleet logistics and using these as fast response groups that need to move with a fleet anyways. I also don't really see a lot of reason for these to have shields and armor as they should never get close to combat.
One interesting idea
(E: once 1.13 rolls out) would be to consider a military support hangar vessel which can be used to repair armor at least on the DDs (at 36k tons I don't think you can achieve high speed and 24k tons of hangar space for the cruisers). I don't know that it would really be practical but it could be worth experimenting with.
