Eddy...my third reef attachment for the clew is quite simple: a cheek block positioned slightly aft of the 3rd reef clew (very similar to those for the first and second reef points) and a reef line that I simply tie around the boom with a bowline. A brief description of my setup can be found here:
http://rollinscs.com/boatpages/projects3page.htm I also needed to add another cleat near the gooseneck to secure the reef line.
My main is a loose-footed main so it is easy to tie the reef line to the boom. I only rig the reef line when I am headed off shore so there is little worry about chafing that may be caused by the little used reef line. The battens in my main are both located above the 3rd reef point so there is no conflict.
I really don't know the conditions in which you will be sailing but I can relate my experience to you when I was in your situation. Libations was my first displacement boat and winds here in San Francisco Bay are routinely in the mid to high 20 knots. At first, the prospect of rounding up and loosing control in high winds or gusts was quite intimidating to me. As I learned to depower my rig I gained confidence in both the boat and my ability to handle her. Learning to reef, having the proper reefing setup, and knowing that I was prepared for nearly any wind that I might encounter all contributed greatly to my enjoyment of the boat. And on the few times that I actually used the 3rd reef, I was very happy that it was there.
Perhaps a 3rd reef for you and your expected sailing conditions is overkill at first and, if needed, it can always be added later. But, based on my experience, it is something that you might consider as you add a new main sail.
