Just back off your full length die a turn or so. If the brass is hard to chamber with this setting, then screw it sown a little at a time until you get a good fit. Size them all this way and load. Next time, if you want to neck size, just use the neck die, not the FL. If the brass gets hard to chamber after several neck sizings, then run them through the FL again. No need to get anal with this, it's not rocket surgery.