that would be a good starting point but doing it that way it wouldnt be that effective since its comparing apples to oranges, they are similar but not exact. Anyhow I posted a while back ago about the strength of US Pacific forts but never got an answer to the numbers in the game. I have come down to the point of several diffrent styles of forts on my own.
1) mortars - basic for beach defense
2) mines - basic for warship defense
3) small caliber guns under 10" - defeats most warships
4) large caliber guns over 10" - defeats most warships
5) beach opstacles - impedes invaders on beach
6) bunkers - protects defenders
Now what each of those represent is the major question.