Subby84 You've got enough space for 4 small and 4 large crew cabins next to the 3x3 gap on the centerline. The actual optimal design is to have zero sensor arrays because they don't do anything except effect the distance at which the AI notices enemies. You'll always see your enemy before they're close enough to shoot.
It sounds like you're trying to balance your power too tightly. The meter on the build screen is just plain wrong. It counts power for FTL, which you never need in combat, for all your engines when you only use part of them, and understates how much power shields can use by about half.
You could use about twice as much power for the shields, and less than half as much power for thrust because you have more than twice as much forward thrust as you should. You should have 1:1 forward to reverse thrust at most on a long range combatant now that flight direction is assigned rather than derived based on thrust balance.
I generally ignore the meter and install one reactor in close proximity per shield or ion beam, one per two electrobolts, and one per six lasers, plus reactors for engines to limit walk time. Walk time is a lot less urgent for engines.
