Thank you for all the nice comments.
The 3m ordered actually measured 3.95m and the pattern matching wasn't very wasteful. I had problems with the cuffs of the dress though, they are cut so that the outside edges are on-grain and with an underarm seam. The plaid pattern at first glance looks balanced/symetrical, but it's not and that's how I managed to mess up the first time I cut them, trying to match what couldn't be matched!