I think you might find that running it a little richer on the LS screw might make it a little less picky on it's idle speed settings. More forgiving all the way around actually (tuning as well as starting).
Yes, it's going to run a little rougher, but I'll take that over an unreliable idle any day.
Have you opened the spark plug gap to .025" or so yet? Sounds crazy, but that will help it burn that richer mixture much better...especially in mid range.