Well, if you have nice micrometer peep sites, you zero it just like a scope. But when you are restricted to just the typical blade sites, you have to get creative. In your particular case, you can file down the front blade, by making it shorter will raise the barrel and impact. Get a nice metal file and work slowly until you get the hang of it. You can get one of the touching up bluing pens, or even paint the top of the blad white or red when you are done.
MEL
MEL