Your Pacific sight probably gives you a higher line of sight than any of the standard sights.  I'm afraid the only choice you have is to install a taller blade.  They're not hard to make, I've even made a few that are .070" wide to make them easier for my old eyes to see.  Your aftermarket front sight might be the wrong height for either the standard sight or the Pacific.  Some have changeable blades, some don't.  Here's the way to figure out what you need.

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