I just bought and installed the Schaefer Snapfurl CF700 a couple months ago. I had the convenience of doing it mostly indoors as I have a trailerable MacGregor so I took the forestay indoors (garage) to measure then put it mostly together across two rooms. (It was too cold outside) Being able to have the mast down and boat in the driveway was very convenient. I cannot stress enough the importance of getting the measurements right and doing the math a dozen times before cutting. When doing your calculations and adding them all up do them again from different points in the equations. Start from the finish and work backwards then pick another point and work from there until all your calculations synchronize no matter where you start from. This will catch those goofy little math mistakes that don't show up so readily but do show up when working backwards or from another starting point because the answers will be different and you will wonder why. Make sure you do the math until it is ingrained in your mind. The 'D' shackles add to the measurements there are three of them, the one on the top end of the halyard swivel has no impact just the other two do. The top of my forestay is swagged and the swag took up some of the forestay length so my foil was cut a tiny bit shorter. Try and allow for an inch or maybe just a half inch between the swag and the black plastic cap that goes on the top of the foil for future forestay length adjustment. The foil should be long enough to allow for a full stretched luff otherwise get the sail shortened by a loft. I had my hank-ons converted to #6 luff tape and at the same time the sail luff shortened for the foil (NorthSails). The Schaefer requires at least a 5/32 wire forstay and mine was only 1/8 so I had to replace it. I ended up getting a complete 5/32 forestay with a new and bigger 5/16 turnbuckle to replace the OEM 1/4 turnbuckle and 1/8 wire so now my whole headsail unit is new.
It is not manually a difficult job, if I can do it any moron can but I will say it is a job prone to making mistakes in calculations so get the math done a dozen times and then get it checked by someone else with fresh eyes. After all was done I thought it was a miracle that I actually got it all together with no mistakes, it was very stressfull. In the end I decided that as convenient an option a rollerfurler is, it is not worth the extra complication it adds to trailering set-up. It took us a half dozen attempts to raise the mast and in the process the heavy foil would knock the jib pulley behind one shroud or another or the halyard would jump off the pulley or after getting everything aligned up there discover that while being focused at the hound we inadvertantly caught a line or wire under the mast step and had to do it again. (we weren't watching the base). There is no way this exercise can be performed over water, we did it all on land on the trailer then launched. There are some small pieces to attach to the roller drum so if you are over water you may want a safety net in place to catch the pieces you drop. Perhaps a hoola hoop with a big nylon stocking around it under your forestay tang. Better have something or Davy Jones will claim the pieces.
Now that it is installed and we have tested and used it we are quite happy with it. I can switch from jib to genoa and do not require a UV strip because I always take the headsail down and bag it just like a hank-on. Next time out I check wind conditions and then decide which headsail to hoist. I only leave it on overnight on weekends. It is a very nice unit and I really recommend it for a slipped boat not a trailerable. We buy moorage and slip for six months a year so I do not have to raise the mast and dance with the furler too much. You made a good choice selecting the Snapfurl, enjoy!