Those on the TC sight are perfect for the GPH, though I can't confirm it on the Pedersoli. Whether on a TC rifle or Lyman you have to screw out the aperture first before installing the rear bolt/screw. It won't go past the aperture, and your screwdriver won't either. Not a big deal. I only use the aperture on mine for sighting in and for longer shots. Otherwise I'm shooting it as a "ghost ring" very much like the appearance of that Pedersoli sight. Fortunately for me, the Lyman and Williams apertures fit the sight too, because I'm prone to losing them when I take them out.