[Christ]

Running low can provide a benefit of windage, as was stated before, but most engines these days are designed to prevent crank splash anyway. The oil pump draws out a certain volume from the pan, so the level in the pan is lower when the engine is running than when it is parked, FYI.

Maybe in days of yore, when engines weren't really designed with windage and the like in mind, it would have been effective. The only real way to know if it will work on your vehicle is to try it for a few tanks, then "top off the oil" and try a few more tanks...

If you have an SGII, you can note your idle fuel consumption at the low mark, then add that last quart and note it again. If you see no change, it's unlikely that it's going to help at all.

Crank splash, at least on modern engines, does not oil the cylinder walls. The volume of misted oil floating like crazy in the crankcase because of the violent motion of air compression and expansion does it. Vacuuming your crankcase does not prevent this, either. There will still be oil flailed around violently.