It never really made sense to me why 1 8,000 ton ship can have only 1 spinal mount, but 4,000 ton ships can each mount the same weapon. Why not make max spinal mount size scale with ship size, or allow multiple spinal mount weapons up to some multiple of ship tonnage?
I agree with this sentiment... a ship might be able to carry a total spinal weapon weight based on ship size, but you don't want it to be a linear...
Perhaps something like...
Ship Size in HS (ShHS), Weapon Size in HS (WpHS)
ShHS^0.5*10=WpHS
A 500 ton fighter could mount max spinal weapons of 220t size
A 5000 ton frigate could mount a maximum spinal weapons of 700t size
A 50000 ton battleship could mount a maximum spinal weapons of 2250t size
Just as an example...