Size of roller furling genny should be dictated by local conditions and typical crew. If you usually sail in 10 knots or less or usually have some crew, get a 150. If you usually sail in over 10 knots or usually sail single-handed, get a 135. If you get a 135, I recommend a raised clew. In either case, I second the recommendation of a padded luff. I also second the recommendation of the Schaefer Snap-Furl 500, but the CDI is a reasonable choice too. As others have said, the functional difference is the CDI's integral halyard system, which is both a blessing and a curse. It is a blessing because it eliminates any possibility of halyard wrap and makes installation foolproof. It is a curse because it makes adjusting halyard tension overly cumbersome. Installing the Snap-Furl is a little fussy because careful attention must be paid to the instructions for avoiding halyard wrap. Basically, you MUST use the halyard fairlead and you MUST have the upper swivel raised to within a few inches of the top of the forestay, which may require using a wire pendant at the tack. For me, it was worth it because I wanted the ability to adjust halyard tension on the fly. -----Original Message----- From: montgomery_boats <montgomery_boats-bounces@mailman.xmission.com> On Behalf Of Timothy JarviMD Sent: Monday, July 30, 2018 8:41 AM To: For and about Montgomery Sailboats <montgomery_boats@mailman.xmission.com> Subject: Re: M_Boats: bow pulpit, roller furling & mast raising Dave, I'm using hank-on sails currently on the flush deck M17 and my twin-head stay Nor'Sea 27 but I'm considering this Schaefer system on the 17 as an alternative for ease when I'm just daysailing. What size headsail would you chose for the furling sail? Tim Jarvi Petoskey MI