You need to put a head on the battens, where you can thread the webbing trough. Then you can tension the webbing and trim batten tension. This is a common system on windsurfers..
Perhaps you should call Calvert and ask them for some fittings, or try Sailrite.com

The leech line is for trimming your sail. There is probably a small cleat or something you can secure it to. It lets you control your leech better, and is very common on larger boats. First time I have seen one on a fully battened square top for a beachcat tough.
If the leech start to flutter, you should tension the leech line enough to remove the flutter. Leave it by if it doesn't flutter. If Calvert got the luff curve right, you should not need it unless you downhaul max and really open the leech.


Interesting picture where the sail is lying flat on the ground. Looks like the draft is designed into the luff-curve.