Do you realize how pointless considering cost is?
-you're talking a 100 mineral difference on a ship that costs more than 2000 minerals for the control & engines!!!
Also, at mid-game tech, Armor maxes out at 4Hp/Kt, shields at >8Hp/Kt.
That's why I also added "Ablative armor", which gives up to 16Hp/Kt, but takes up one space.
That means you can easily lose 75 components (1200hp) of armor in a battle, and spend the next year in spacedock
Big tradeoffs there, works great.
Emergency defence forces get all armor, since they only have to win one battle, and can afford 20 turns of repairs. Attack ships usually get a mix of shields & armor. Long-Range Missions will go All Shields, since they can't repair.
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Now consider the fact that these are BASESHIPS, so tech cost is not an issue. shields provide twice the HP of unmodded armor, so phased shields are much better against BBPs that armor is.
Ablative armor was layered on these baseships, about 70 tiles thick (1100 hp), but they couldn't have all armor, since they only had 16 repair per turn, and needed to be always on the attack.
One ship's armor got ripped through on the first volley!
Putting 500 tiles of Ablative Armor on would have given them 8,000 hp, but they would never be finished repairs, see?