You will gain some. Is this a sativa heavy plant as it looks like it? You didnt count the first 7 days of 12/12 as flowering right as day 8 is day 1 of flower counting.Then id guess 9 plus weeks for a sativa heavy plant
it will pull 1 gram. you can never tell unless you have grown that exact pheno multiple times.. Density can change while drying. some buds shrink more than others too..