NA do you use the sport straps? Right and left? Or two of the same?
My primary strap is the RS-4 (not sport), and my other one is the RS Sport-L (the left-handed one). To be honest, when I first came across the left-handed strap, I didn't understand the purpose. The shutter button is on the right side of the camera, so you're going to have to pick it up with your right hand, regardless of which hand is dominant. I recall thinking, "Who designed this, Ned Flanders?"
Then I got my 600 II. When you're carrying a supertele and want to lift it to handhold a shot, lifting it by the camera body is not a good idea, and you need to keep supporting the lens with your left hand. So in that case, carrying the combo on your left-hand side actually makes sense.