LSA or Duration to fine tune glasspacks??

If a person wants to fine tune the sound of glasspacks, would LSA or duration have the greatest effect on fine tuning the sound of the glass pack to make it sound more like a glass pack should sound?
We all know on a 4 cylinder sounds like a terrible weed eater because of the order of the exhaust pulses. We know we can delay or speed up the order of exhaust pulses with the cam. So which would be the best way to accomplish this, LSA or duration?