Ronmar, I use a 2-point sling also. I find the RFB too heavy for a single point. If I have to move, run, or do anything requiring me to use both hands, the heavy beast swings around too much for my taste. As I mentioned, preferences and situations can be all over the board for the individual.
Personally I don't like single point slings on anything but an AR pistol, SBR, or other short weapon. I got to try out an HK MP5 on a single, and it was pretty good. Two-point slings have gotten so well designed with so much instant strap adjustability that I find little reason for the single. Again...for most of my weapons and situations.
Ronmar, on my 2-point Magpul MS-1 on my RFB, I used that tiny strip of pic rail on the bottom of the buttstock. I installed a 45-degree Magpul QD mount facing left. On the front I installed a Magpul 45-degree QD on the end of the top pic rail facing left. I like the sling points and have had no issue with this setup.