Just to pick up on that...
IIRC, the Light Weight armour mod' is almost completely redundant.
Whenever you're considering modding armour for light weight, it's almost always better to just go for a light-alloy hull (which weighs zero) and then apply HD to it.
Even if you have to add an HRP to gain more integrity, the result will be lighter (and usually much, much, cheaper) than buying different hull and modding it for LW.
About the only time it might be useful is in a ship with limited internal slot-capacity and where you want improved integrity and minimal weight.
And, let's face it, if you're that desperate to minimise weight, you probably shouldn't be worrying too much about integrity.
