The hit & run seems to be a pretty basic tactic to me, so it's interesting that you could finish the game probably multiple times while abstaining from it .
But it can be perhaps made even more effective in the turn-based mode: when you see the enemies, pause, then shoot them, and if any of them get too close, do a U-turn back and only after that go back into the realtime mode. Then run like a bunny. Rinse & repeat.
(By the way, if that sounds mindless, it really is. That's why I don't like the combat in MM6 very much, and that's why I don't play the game all the time .)