How-To: Space Combat
Don’t try to tank them at all IMO. Open with either nuking one ship immediately, or if significantly outnumbered with boosting away to draw them out into a long line—they often seem to have different top speeds, so they spread out and can’t all fire at you at once.
Go on attack runs with the intent to deal hull damage (they don’t seem to repair it) to one ship before you withdraw. If you have all the engine perks you should be able to boost out when your shields are low to recharge, though it might take more than 1 boost to clear weapons range so don’t wait too long.
Using a full weapon group of missiles with 1 pip of energy will let you fire the entire stock of missiles just fine. The energy seems to only dictate how fast they reload, but with hit and run tactics you can put energy in them to reload during the ‘run’ phase. This lets you take out their shields with lasers or particles (for range) then fire all your missiles and leave.
Doing that seems to work fine for me, even with only A class ships. It does take skill points to get working though, particularly for speed, so it’s not great in the very early game.