Has anyone had experience with Ronstan's "Ballside" batten and intermediate luff cars . I am thinking of using on my new mainsail on my 35ft Martz yacht. The Ronstan literature shows that they require no track system and fit in the existing luff grove. It seems that inside the luff grove they are fixed metal on metal but have roller bearings for raising and lowering main on the extarnal mast face. I assume this works OK for raising and dropping with no power in the sail.
I would appreciate any help on this issue before I spend hard earned boat units again.