Thoughts on a Donegal (Irish) tweed for an Argyll coat..?

[Graeme H]

Out of curiosity, how many meters of fabric does it require to make a kilt jacket and waist coat? (Assume double width)

As Luke rightly mentioned, there are a lot of factors. Generally however a gentleman's girth doesn't play as much into the equation as people realise, but his height certainly does. How a tailor faces the jacket and waistcoat also is a factor (I frame all of my jacket in-breast pockets with the facing which requires a little more cloth), and also if there's a pattern on the cloth then the repeat is a factor. And also yes, a cloth back on the waistcoat will add more cloth, however I typically recommend strongly against this unless the waistcoat will be worn exclusively as a separate and never with a jacket.