'31, I have used the 3 point, the single point, conventional 2 point, and on my tactical type of rifles, 3 point slings converted to 2 point.
My current 3 gun match rifle has the Ace long buttstock, but it is about to be converted to an A2. I use a conventional 2 point carry sling on that rifle, because I am always holding on to my rifle when performing transition drills in a match and shooting my side arm one handed. I use the carry setup so that i can sling up for long shots.
If you want to have your rifle hanging in a low ready, that is fine, but may not be too practical for your big scoped rifle. The idea of a 3 point is to allow you to drop the weapon and transition to a side arm quickly. i don't know how often you will have to do that shooting in the open country. I would recomend a conventional 2 point carry setup as ling as the big scope is on. You could convert to a 3 point if you change to iron sights. JMO though.
My soldier son (in the desert right now) got me away from the 3 point to a converted 3 point to a 2 point. This allows for quick transitions, but there is not a strap running down the left side on my rifle getting in the way of the controls. Both his M4'gery and my CAR15 have this 2 point set. My 20" rifle actually has a single point setup that can be changed from a 2 point carry set to a single point set in just a few minutes.
Please listen to others who will comment, and try many setups. You will probably end up with many sling sets, like me!
My rifles.
The M4'gery and the CAR 15
