Well here's my take on large craft "fuel" use rates

Ships mass in tons, "fuel" used per day at 1G in tons and the amount of "fuel" points per ton of "fuel"

`Naval capital "fuel" use rate`

2,000 to 49,999.........25t...10

50,000 to 99,999........50t...9

100,000 to 149,000......100t..8

150,000 to 199,000......100t..7

200,000 to 299,000......200t..6

300,000 to 499,000......200t..5

500,000 to 999,000......400t..4

1,000,000 to 1,499,000..400t..3

1,500,000 to 1,999,000..800t..2

2,000,000 to 2,500,000..800t..1

Dropships

under 1,000t.......4t...80

1000 to 4,999......6t...70

5,000 to 9,999.....8t..60

10,000 to 14,999...10t..55

15,000 to 19,999...14t..50

20,000 to 24,999...18t..40

25,000 to 39,000...22t..30

40,000 to 54,999...25t..20

55,000 to 69,999...34t..15

70,000 to 84,999...42t..10

85,000 to 100,000..50t..5

Not the most realistic but at the lest it avoids the silliness of having any ship above ~300,000 tons only use ~39.5 tons per day... Also all dropships use this chart, instead of military getting a free pass...

An alternative is to use 1/2,000th of the ships mass as the tons per day at 1G, I.e. a 500,000 ton destroyer would use 250 tons per day. An endurance of 100 days would require 25,000 tons of "fuel", which is a fair bit more than the ~4,000 tons B-tech would use.

I also would like to up the mass on the armor so that the mass for a point of armor is closer to this.

Standard: 30 tons/point

Improved Ferro-aluminum: 27.5 tons/point

Ferro-carbide: 25 tons/point

Lamellor Ferro-carbide: 22.5 tons/point

Possibly with the ships max armor being noted as say one point per 250 tons of ship (a 1,000,000 ton ship can mount up to 4,000 points, as such a ship with max armor would spend around 9 to 12% of it's mass on armor)

with the increased armor mass and fuel the KF drive will have to get lighter, so 33% for the compact and 75-80% for the standard drives I think should be enough.

I would also more define the crew, the Crew for large craft and military would have a base crew of 1/2000 of the the ships tonnage (a 1,000,000 ton ship would have a base crew of 500), Gunners remain the same. Now the ship requires cooks (1 per 50 base crew, gunners, officers, and others), 1 medical team (of 5) per 150 personnel, launch crew is 1 tech team per launch capable door plus one per squadron of aerospace craft (including small craft, 6 for IS 10 for clan), and 10 personnel for the coms gear.

Officers is 1/5th of the above totals (or 1/10th if you want a few less officers...) round normally

So for a 500,000 ton destroyer that requires 30 gunners, and 4 launch doors and 3 squadrons of "aerospace craft" it would have a base crew of 250, with 7 tech teams (49 personnel), 10 com techs, 15 medical personnel (3 teams), 9 cooks for a total of 363 crew, this requires 73 officers for a total 436 personnel.