You are smart to stay away from the 3 point, "tactical" and "Giles Stock" type slings. They are more dangerous than helpful, IMO. A single attachment point is probably ideal for your run and gun matches I think.

Regarding the Magpul cinches and multiple magazines, 30rd and drum magazines: My favorite are the 20rd mags, as Uncle Sam intended. I only have the cool cinched 30rd double for gee whiz factor, and use my 20rd versions when shooting!

The rear 40L sight was chosen just because I liked it. No ACOG or any other high dollar toys in my future!