Production costs of different weapons in WW2

From sources such as Harrington (Six economies in WW2) , Tooze (Wages of Destruction) Ellis (Brute Force) we can get reasonably accurate figures for how many tanks, aircraft, naval vessels etc each major Power produced. And Harrington gives figures for the % of GDP taken by military expenditure so we can compare how much was spent in "real' 1990 USD using OECD estimates for GDP*

However, does anyone know of a rule of thumb that can help decide what different production options would be open to any country?

Something like so many tanks or thousand tons of ammunition = X barges or Siebel Ferries or Submarines for Germany in 1940 or 1941.

Or how many ASW escorts = one CV or BB for the UK.

Any ideas?

Some Grand Strategy level wargames do rough approximations for this. Are any of them usable?

* Caveat regarding figures for the UK as some might include production in colonies or Dominions.
 
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