I have never paid any attention to the NMRA weighting recommendations and couldn't begin to say what they are. For styrene cars I use what I am given. For resin cars of any kind I use I use six of the 1/4 oz. sticky weights in a strip. Exceptions would be resin flat cars which get what ever fits underneath and resin hoppers which get basically nothing beyond trucks and couplers. I also run empty Kadee 2-bay hoppers with no added weight. I have no derailment issues. Carefully laid track helps.
