[Suicide Junkie]

1) That seems to be a hangover from SE3.
In SE3, the SRs went
I: 1/2
II: 1/2 cheap
III: 2/2
IV: 2/2 cheap
V: 3/3

When SE4 came out, and all damage rating got multiplied by ten, so:
I: 5/20
II: 10/20
III: 15/20
IV: 20/20
but, the sequence got screwed up here
V: 25/30

The SR V should be 20kT in size, or provide 30 regen.

As for designing ships for the AI, you could have a big effect of the game by designing ships that hit the weaknesses of each enemy you face, but the AI will not make the best use of your ships strategically or tactically. If war opens up on multiple fronts, the AI might use the wrong design against each enemy.
Good Luck, though!