Well, the problem is that if you give Warships some sort of special resistance to normal scale weaponry, fighters suddenly become useless against them.
You'd have to pair that up with some way of indicating how many guns are being fired in a bay.
For example, assuming the
two sets of weapons, you would have two weapon lines:
Bay 1: CERLL 600 (6000 std) (heat) (various shorter ranges)
Bay 2: HNPPC 600 (6000 std) (heat) (various ranges)
But if you changed it to include number of weapons:
Bay 1: CERLL*600 (6000 std) 600 (heat) (various shorter ranges)
Bay 2: HNPPC*40 (6000 std) 600 (heat) (various ranges)
Then you could have a simple set of math. If a target ship has 1 standard pt of resistive armor, then you subtract (the number of weapons * amount of resistive armor) from the standard damage being delivered:
So the CERLL Bay would do 5400 damage: 6000 - (600 * 1) = 5400 standard damage
The HNPPC bay though would do 5960 damage: 6000 - (40 * 1) = 5960 pts of damage
If the target had 5 pts of resistive armor, then the calculation would be:
The CERLL Bay: 6000 - (600 * 5) = 3000 standard damage
The HNPPC bay: 6000 - (40 * 5) = 5800 pts of damage
The types of weapons would not make any difference, as mixing weapons with different damage output would make the bay less effective against resistive armor.
For example, instead of using 600 CERLL, you use 300 CERLL, and 600 ISML:
Bay 3: Mixed laser*900 (6000 std) 600 (heat) (various ranges)
1 pt of resistive armor means this bay will only do 5100 pts of standard damage (6000 - 900 * 1). The pure CERLL bay above did 5400 pts of damage. Technically the bay should be doing some damage against 7 pts of resistive armor (300 CERLL * net of 3 pts of damage each = 900 standard damage), but in the interest of making the math easy I am not going to bother with that.
At 5 pts of resistive armor, inner sphere small and medium lasers, along with Clan small lasers are no longer useful for damaging hardened armor hulls. Fighters would have to use AC/10, AC/20, PPC, and similar weapons to do damage.
LRMs would be treated as 5-pt hits, SRMs would be 2-pt hits, though you'd want a critical hit table to reflect the fighters trying to target critical items on the surface. The problem is the fighters have to get close to avoid massive to-hit penalties, and the ship they are targeting is likely using a jammer that is more massive than their entire squadron.
This is similar to another mecha game where the resistive armor in a location was equal to its current armor points, divided by 10, FRD. So a 50-pt slab of armor would be immune to medium laser hits, but a 49-pt slab of armor repeatedly hit by medium laser fire would fail after 23 hits (and the first 10 hits only bring it down to 39 pts of armor).