i was more thinking about weapons, ship balencing would be more difficult. you would need to calculate its thrust capability, its rotational capability, its weapon compatability and number of banks (a 4 point bank is twice as effective as a 2 point), the power of compatible weapons, max missile/ammo load. also stuff like hitpoints, shields, ect. there are alot of interacting variables so just adding up points may not neccisarily work.
you may have to give each variable a wheight, or how much capability that variable adds. for example shields would get a higher wheight than hitpoints, as theyre rechargable. also one must figure out how to handle binary flags, such as stealth, which may be worth a number of points. im not saying its easy, but it is a math problem and it can be broken down. its just a matter of how accurate a formula you can come up with.
it really just requires starting a spread sheet, plugging all variables for the objects you wich to compair, and thencreate a formula to determine a total brownie points value. mace a number of ships comply with the formula to have ~equil brownie points. you use playtesting under the rules of science to either confirm or reject the new formula. play the same mission 3 times each with a number of ships. and compair average mission scores per ship type. tweak the formula untill the differences in the point scores occupy a lesser spread. you want the brownie points to corelate with the scores as closely as possible.