Mass by default in Weldment properties + Cut List ?

We need a "Mass" or "Weight" column in all cut tables displayed in
drawings, which requires each weldment in the part to have a "MASS"
custom property which can be automatically updated through a
definitition like
"SW-Mass@@@Article-liste-des-pièces-soudées1@weldment_box2.SLDPRT".
Fine.

But how can we avoid to manually insert that property in each item in
the part's weldment list ? How to do it automatically, or have it by
default ?

Thanks !