You should know the bore diameter, ie: .740, choke diameter or amount of total construction, and minimum wall thickness in each barrel. The important spec is the minimum wall in each barrel, top, bottom side of each barrel. You cannot take the outside diameter and subtract the inside diameter and divide by two to get the wall thickness, you need to measure with a wall gauge.
From the specs you list, I am assuming the left barrel .736 is bore, .695 is choke dia and .054 is wall.
If your numbers are correct, that should be a rather heavy gun.

Dennis Potter