H pipe placement

I just finished building the new 3" stainless for my Duster with stainless flowmasters and T's for the H pipe so I'm asking a lil late but why not. Does anyone know if there's a "sweet spot" to put an H pipe as far as maybe distance from the headers? I thought there might be some kind of rule of thumb for it. I just put it where it fit best and wasn't in the way of anything. Anyone know?