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 .)