Although I could derive the math myself, to save time, do you have the formulas you used to compute your example?
Uh, i just grabbed the nearest spreadsheet and made the calculations in a sketchy manner. As result, they are all gone now.
So, if we get the conversion ratios nerfed, and making a proper fleet composition becomes (relatively) important, we want that task to be interesting, right?
Right now, most M/C values seem very arbitrary and random, so for a large fleet the uneven ratios will generally cancel out, resulting in a total fleet cost ratio close to 1:1.
We dont want that for every random fleet, right?
I think we should pick some duality, and make one side very metal-heavy, with the other being crystal-heavy.
At first i thought offence-defence, but that probably wont work. Defences are more of a one-time inestment, while fleet needs replenishing more often. So it wont be possible to balance at all.
So, how about fleet ships - starhips duality? Fleet ships cost mostly M, starships cost mostly C. Highly specialised starships and fleetships have very skewed ratio; more universal ships like fighters and flagships stay closer to 1:1 ratio.
That would cover mobile things, and for defences... how about large buildings mostly cost M, small turrets cost C.