RWS, Norma, and Lapua have smaller flash holes than the cheaper brass or American brass. Unless you believe first of all that you are better with a metal gouger than the people who built the brass then leave it alone and second of all if you do not need the extra ignition leave it alone. You might take a look at the US Palma team which is sponsored by Lapua and Norma and they asked Lapua to build 308 brass with small primer pockets so they would get less ignition. I bet they aren't gouging the flash holes with sharp tools.
Been down the road of do a few and not do a few and that will give you variable ignition for certain.