Underbite : should I have my upper jaw brought forward, or my lower jaw set back?

I've read the having the upper jaw brought forward can make the nose look bigger/rounder. I want to avoid this as my nose is already big and round. Then, with having the lower jaw set back, my chin may look more recessed and weak. I'm not sure which route to take here, answers are greatly appreciated. I want to do what will look best.