It doesn't look all that bad, you are on the right track. You could sew about 6 to 12 inches of 550 cord to the end of your sling in a loop and it would look just like something you bought online. Just loop it back through itself and cinch it down and tape it. Check out Way of the Gun's minimalist Proctor Sling, or even the universal wire loops that Blue Force Gear sells to make attachment points where there are none.