I’ve used the Bikesmith press and cotters, the press is OK but I replaced it with a Park cotter press that works better. I have never had to file Bikesmith cotters, if your spindle is in good shape you shouldn’t have to either unless you are buying the cheap flattened cotters that tend to bulge. I put a little anti seize compound on the cotter making sure to keep it off the machined flat and use the park tool to press it in. You should never use the nut to pull the cotter in place. Once pressed into place screw on the nut and snug it up, ride the bike, press the cotter again, snug the nut, that should do it.