Your draw length is your draw length. Your string loop will affect your anchor point but it won't change your draw length.
I agree with this 100%, TFox. It comes down to "which came first....the chicken or the egg". To find your proper DL....you need to know how long of a loop you're gonna be utilizing (to hit your proper anchors....whatever they might be). But if you have the proper anchor points down....there's only one draw length that will be correct. Right?
So....if you then change your loop length....what has to change? It certainly won't be your DL. It'll be your anchor points.
Am I seeing this all wrong?