My boat has Doyle Stratis sails, Doyle's version of 3DL's. No problem with the sail in the boom. Sets nicely with the mandrel. You will no longer have an outhaul or cunningham with the LeisureFurl. To flatten the sail, simply cleat the halyard and tighten the mandrel. Off the wind, simply loosen the tension on the mandrel and the sail fills out.
You will need to work with your sailmaker to either make a new main or modify your existing sail. The LeisureFurl has its own bolt rope and tack/clew requirements. No doubt, your North loft has made sails for the LeisureFurl before.
If you PM me your e-mail, I can send the document I have from Forespar for the boom. Reading the document, the model is referred to as 19/6.