Thank you both Dave and Craig,
The battens my sailmaker is proposing to use are not the ones I sent links on. These are made of stainless steel and he has had good experience with them in other boats as long as there is enough space on the mast, as I said.
I know about the vertical battens, and would not even think about using that on my SM. Imagine you have to bring the sail down with them in place!. Also, if the furling is not exactly perpendicular to the battens, as somethimes happens when the blade twists when furled under some wind conditions, the vertical battens will corck screw and jamming is almost assured. A terrible sail shape after a little sail stretch is something else that I cant imagine seeing on my boat.
The idea with the Roller Battens is not to create a huge positive roach, but to add some sail aloft. So, it is not for use as full battens, but just for the last 3 or 4 ft near the lech. I will chack that article, Graig, thanks again
The link is:
and they are called "Roller battens" Page 41 of their manual