Might be a pretty good fit for a proa - if you watch the video you'll see that it requires wearing-away when "tacking". Sortof like a fully balanced Balestron rig, with the boom higher and sail below the boom.
You might have to sign up to see the video
http://outrigmedia.com/outrig/uncategorized/2011/10/19/diamond-rig-designed-by-john-marples/
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