Heavier MT like a HPI Sav Flux - 3.5v/cell is a good lvc, helps protect your lipos where there are big voltage demands. If your RC is lighter can go with a lower lvc, like 3.2v/cell. I use 3.2v/cell in my Slash.

Using the auto lvc setting even with a specified voltage has one quirk - if you run your lipos down in one session and quit, turn it off, unplug and then come back later to finish without recharging, you can get into trouble. Say you've dropped the voltage enough and when you come back to run somemore, the MMM thinks this is a 3S since the voltage is low enough. The lvc setting on 3.5v/cell will now be applied to a 3S and the MM will allow you to run this 2nd time down to 3 x 3.5 = 10.5v which is fne for a 3S, but will seriously risk damaging a 4S that shouldn't go below14v.

The only clue you get is the number of beeps the MMM makes when it powers up - you would only hear 3 this time and not 4. I never run again without recharging, but this is an easy way to damage lipos. Its something you wouldn't think about. Always pay attention to the MMM when it counts back the number of lipo cells and if its the right number, it doesn't matter. If its one too few, do something before you damage your lipos.