How many yards of material does a standard tartan kilt need for a size 50 or so waist? I am guessing about 7 yards of material should be enough, but I have read that when making a tartan that they were originally made with 9 yards of material... However I have also seen 8 yard, 5 yard, and 7 yard kilts advertised, so I wasn't sure how much a person with a 50 inch waist should probably be looking at using when making his own first kilt?

As an additional question, how much material is needed for fly plaid's?