Obviously, if you're hitting low as you describe, you need a lower front sight. Do you have a stainless gun with a pinned front blade, or a blued gun with the blade integral with the base? If the latter, the blade will need milled off, with a lower blade fitted, drilled and pinned, if you are going to use a fiber optic.
As KRal suggests, Gary Reeder can mount an FA base. Call them.