I said reach the calve as I believe you would also want some protection between the kilt selvedge and the hose top. But not so long as to reach the flashes on the leg. So in my case, if the kilt stops at the top of the knee, the knee cap is about 3.5 - 4" , the hose cuff starts about 3" below the knee cap and is about 3" down to the bottom where the flashes are now visible...I'd say the bottom of the cape should fall about 6" below the top of the knee.

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