On your recent designs, I think you shot above the goal with the fuel storage.
I'd reduce it to 300k, get an extra engineering space or maybe a level of armor (2 or 3 is ok for a start, generally, so your not bad off) and increase the Resolution of the Scout to 100 (geared for 5000 Ton ships).
Also, if one of your ships is a little ligher and a little faster than the other ships, that doesn't actually benefit you that much.
Maybe on Area Defense/Anti-Missile, allowing maneuvering.
Good missiles this time, reasonable range, shorter than your missile armed opponents most likely, but good enough to fight an enemy at range, really good speed for the tech level, and a size 4 warhead.