Welp never mind tashkin says its "impossible"
Could still though have this weight system just increase damage on guns, higher damage guns slow people down while low damage ones have minimal losses. This would especialy be great for medics as lower tier guns will benifit them more since they will have a massive speed manuverability bonus over people running with higher damage guns. They heavy guns will still have a small kill time advantage though if no damage losses.

Also i think this is going to not happen because those pesky sparrers pretty much run the entire ZP forums and they are loud and very obnoxious. With how bad the last experiments went and ****ted all over spar i doubt this will happen. Even though its a good idea.