I have a TRG22, and went with a sling design that is different from the ones here...although I really like the tab sling design. The sling I have is one very long piece of webbing that when pulled together has three pieces of webbing laying onto each other and it functions like a standard military strap sling to,stabilize shooting. The sling can be tightened, or loosened like any webbing sling. However, when the sling webbing is let out, there are two long loops of webbing that allow you to carry the rifle like a backpack.
I find the versatility of this sling very useful. Like most people with precision rifles, when using my bipod, I don't also use the sling. If I am shooting without the bipod this sling works like any other quality webbing sling.
The only minor drawback of this sling design is that your swivels have to be sewn into the webbing. Because I sew in my own swivels and buy webbing and the two standard slider buckles (the standard sliders on most GI slings) at a local surplus store, the sling ends up costing me around $5 total.