By all means CW if you have a one shot weapon that will fit on a small ship and take out an enemy with that one shot regardless of size, armor, or shields, then small is definetly a good way to go with that. But beyond the subverter there is no such weapon I am aware of, so for non Psychics larger is better when facing Tailsmans. And I wouldn't get too attached to that strategy. It's likely to get patched out in the future. It's a pretty cheese tactic. You shouldn't be able to capture a ship with a subverter because you destroyed the master computer. The ship doesn't spontaneously grow a crew when the computer is destroyed after all. The problem is that ships are immune to the subverter if they have a master computer. This is wrong, they should be immune to the subverter if they
don't have a bridge/crew quarters/life support.
Puke, I think you are too married to the ship tonnage is displacment thing. If you simply view the ship sizes not as tonnage or mass, but as a measure of the size of components that they can contain, then external mounting using less of that space makes sense. In that case you would still take up some internal space as you need to have mounting equipment, hard points, etc. But they might not take up any more internal space than armor.
These ships function in a vacuum afterall. How do you displace vacuum?
Geoschmo