The buds don't really shrink in size just water weight. You would have to scale at harvest, then calculate stems, trim and leaves. That is just too much work for no reason. Not to mention no one formula would work for every plant and pre harvest trim. I know a quart jar with an air gap for curing is roughly 2.5oz and that is close enough for me. I have 15 gallons of vacuum sealed jars but no accurate weight. Only time I scale is when It leaves the property because there is a carry limit here.
Depending on how dense the buds are, A full quart jar wet is roughly 2-3 Oz dry.