RBS or Sabre may have the batten caps. Would be surprised if Calvert did not. That style is similar to what windsurfers use. A good windsurfer sail should have them.
My most recent set of my sails used that style. Very easy to tension.
3 of 4 of my cat sails have leach lines. Hobie has had them on sails for years. Nice to have that adjustment as sails age and stretch.
Sail fast, Tom G