100ft x 23ft x 8ft. The calculation then is
90 = 100 x 23 x 8 / 207. The usual way is round to the closest ten lasts. Of course, we are used to dimensions written in Amsterdam feet. The dimensions in Amsterdam feet are
109ft x 25ft x 8ft-8in. The size in lasts, calculated from Amsterdam feet is
120 lasts = 109ft x 25ft x 8.727273/207. You can see that the size in what I call "Amsterdam lasts" is about 1.3 times greater than the size in "Rotterdam lasts".