I searched this forum for weighing cars and reference NMRA recommended weight practice. It says 5 oz + 1 oz per car body inch length, The fine point is, do I include length over coupler faces (mine are the "claw" types) or just the body, period?
Answering my question would be just the body. I am sure total end to end length adds insignificant weight to car. My take away from NMRA and other Google reads is to get all cars within ball park weight rather than down to the last precise 1/10th oz.