Reddit reviews Canoe Rig: The Essence and the Art: Sailpower for Antique and Traditional Canoes

If you can find this:

http://www.amazon.com/Canoe-Rig-Essence-Sailpower-Traditional/dp/0937822574/ref=sr_1_1?s=books&ie=UTF8&qid=1410192750&sr=1-1

or this:

http://www.amazon.com/Working-Guide-Traditional-Small-Boat-Sails-ebook/dp/B00KWGYCVU/ref=la_B00J4WFQ4K_1_3?s=books&ie=UTF8&qid=1410192788&sr=1-3

in the library you might give them a look. The first is worth buying. The second is not in my opinion, it's pretty basic. Once you read it you won't look at it again.

To answer your question, I'd tie a small line to the grommet, then take two or so wraps through the eye at the end of the spar and back through the grommet, then tie off with a couple of half hitches around the yard and line. If you put a cleat on the yard you can cleat it off, and then adjust the outhaul tension as needed, although I've found that not as useful as you'd think, on a lug I usually set the tension tight enough to take wrinkles out and forget it.