I run QDs on my rifles, left side of the stock close to the butt, and left side of the handguard, spacing them far apart gives me more room to move, and the sling in front of your hand on the guard works better if you use it for stabilization at long range. Moving the front attachment point twards the rear of the handguard keeps it out of the way, carries the rifle tighter, and allows it to snap up a little quicker, better for shorter rifles and shorter ranges. Single point is a niche, I run it on occasion in competition when I have to dump or pick up a rifle quick, or transition to/from a handgun and there isn't much movement needed. I run the QD either in the end plate or front bottom of the stock, and either hold the rifle, or slide it around to hang on my left side with the grip forward, doesn't work if the rifle is long. The Magpul sling system works well enough for my needs, and the MS4 allows single or 2 pt with dual QDs, but if single point isn't needed, then there are plenty of quick adjust 2pt slings, Namely the Vickers and it's competitors, as long as it has good hardware and is made by a reputable company it's mainly just personal prefference