Leave the pep visor in until you have the helmet fiberglassed enough to be rigid, or leave it in through the entire fiberglassing process. Then cut out the pep visor with your dremel or other tool to make the opening for your real visor. It does not matter what pep file base the helmet is, MOZ, rundown, or any of the MK VIs or other permutation helmets, it is always a good idea to leave the pepped visor in place when fiberglassing.