RE: ok all you pro's
It starts with a balanced and broken in string.........if your string is creeping you'll be turning and fighting both forever.
You need to first tie in your loop properly so it sits straight back at rest.........
Melt the first knot before you tie........tie your first knot and PULL THE CRAP OUT OF IT!! with pliers, get it to seat as tight as you can.
Then tie in your second knot and pull it tighter than you want your finished loop to be. Clip the tag end to within 1/8" and melt it down into ball against the knot itself.
Now stick a pair of needle nose pliers into the loop or use a screwd river etc. Something to really seat the knots.
Hold the string in one hand and pull the loop with the other as tight as you can.
If the knots are seated properly they won't want to spin.
Square the loop up so it's straight back directly in line with your peep and you should pretty much never have to worry about aligning either one.
After you have the loop tied in then set your peep to whatever height you want and make sure you square it up to your eye at rest (assuming it will come straight back on a balanced bowstring)
If you have your peep squared and your loop coming straight back you should be good to go. A little care in set up will save you lots of fussing down the road.