Tom, I did have the system on my Nacra 5.5 with spinn several years ago. The lines were constantly twisting and causing choke-up between the line and blocks to the tack line. But with the new Dyneema type lines, maybe that's not an issue anymore. Which ever system you use, the key is to practice until you get it down to a few quick pulls and be gone.

One thing though, on my take-downs, I leave it up until I am well inside the leeward gate and I can snuff it nearly all the way in with only the tack out, while turning upwind, and even finish the snuff by releasig the tack while going upwind. You cannot do that with the single line system as the tack will be free and blowing you backwards. What ever, just pick one and get used to it so you can do it quickly.