ORIGINAL: Dairy King
You DO NOT loose draw length! You only have to anchor different. If you shorten your draw when you get your loop, then your draw is too short now. Your string should just touch the end of your nose, and if it did before you had the loop, then you shorten your draw to ger your anchor back, your string is not touching your nose anymore.
I guess everyone does it differently, however I shoot better with a string loop if my draw length is shortened by 1/2" or so............if this means that I can stack arrows at any reasonable distance slightly shortened, as compared to not stacking arrows with the same draw length, I will shorten it every time.