If the sling is tight enough to use as a real shooting sling, your still going to have issues with the QD on the 'opposite side', that said if your transitioning side/shoulder - its likley inside and your not going to have the sling max tight.
I really prefer just moving to the gun to the opposite shoulder - it really keeps you closer to the obstacle your trying to clear anyway, and is dead quick if your needing to cover down a hallway, or out an opening.
That said I started running my sling out further on the rail to use as a better shooting sling - and I use the sling socket on the stock, not a recevier mounted position for 99% of my weapons usage.
I have about 11 VCAS Slings -- I run the padded on my 7.62 guns, and the unpadded on the lighter guns.
That said I am very looking forward to BFG's new Sling intro at SHOT

Really more for the 5.56mm and lighter guns.
I tried the MS-3 on our PDW and SR635 - but I dont need the thicker material on the light guns.