First of all, never trust plastic for cleats, whether V cleat or clam cleat or cam cleat. You need to tie your battens in with a couple of half-hitches (or whatever knot works best for you).
And, obviously, this is going to sound really dumb to all you high-tech sailors, but Rick and I don't like to have to try to get everything dialed in perfectly again every time we sail, so we always tie our battens in at the beginning of the season and we leave them that way until the end of the season. In Florida, that means forever.
I can almost hear the groans from the purists who believe in relieving their batten tension whenever they are not sailing -- and those like Jake, who want to be able to change their batten tension easily and quickly. So, please don't follow our example.
But, on the other hand, we have paid our dues when it comes to battens. Rick and I are from the same generation that back in the 1960's used to be up all hours of the night before a regatta shaving battens to get that draft exactly right in the sail from top to bottom. And we would lay the boat over on its side with the sail up and roll a marble down the sail to make sure the symmetry of the draft was correct. If not, more shaving. I'm sure that yacht clubs up and down the East Coast still have fiberglass particles in their yards from all the shaving cat sailors did back then.
So when people worry about how to secure their battens at the ends of the pockets, that's a minor problem compared to what we used to go through in the search of perfection.

Thank goodness for tapered battens.