Yes, an experienced sailmaker needs the dimensions, shape of the roach, the location of the reefing cringles and a photo of an p22 sail, that he can notice, that it is a sprit not a classic marconi-boom that gives the shape. He must know, that the sprit is poked through the cringle at the clew for beefing up the corner of the sail a little bit. It will be good to give him information what kind of masttrack you will use. This link may help him for understanding your needs better: http://bandbyachtdesigns.com/why-a-cat-ketch/ Perhaps, before you can talk with Graham about if battens or not?