As for the nuclear issue, I think you should keep a separate counter for warheads and another for ICBMs. The cost of building the entire US arsenal from 1945 to 1996 was a mere 409 billion. (which is little considering that's over 70,000 warheads) At peak production the US churned out 7000 warheads a year. So warheads are rather cheap once you have the facilities. Maintenance and storage costs a fair bit more, so be sure to factor it in. Modern MIRVed ICBMs are 70 or so million $ per unit, meaning they are more expensive than the warhead (which is around 5 million $). I would probably make 10 warheads per 1 EP and 5 ICBMs per EP, just so things dont go out of control and you can account the rest to maintenance and storage costs for the weapons which are quite high and thus plausible.