I am getting a new sail and Stack Pack built as close as possible to my old setup, which I have been very happy with. (More below *.) I have some questions about these blocks and clips. Do the blocks - in conjunction with the batten in the top of the Mack Pack - tend to make the whole setup self-leveling? Or do the blocks allow the heavier parts of the sail to pull down and mis-align the top of the pack?
I ask because right now my Stack Pack has battens in the top and a web tie point to match each of the padeyes up on the boom. Lines dangle down and tie to those tie points. When putting the sail back on (which I will be doing in a couple of hours) these tie points get tied and re-tied until the batten is in a straight line. It is important for the batten to be in a straight line because my setup has a piece of sailcloth which extends across the gap from the top edge of the Stack Pack (on each side) to the sail. So when the sail is set, the stack pack is actually partly supported by the sail and it curves in and becomes part of the sail. But it is fussy to get them all aligned correctly. I wonder if these blocks would make it easier.
Do the clips chafe against the sail when it is up? That’s a big worry with my setup, given that the top edge of the Stack Pack rests against the sail. I might still have to just tied them off rather than clipping.
Is there still a 1:1 ratio of boom padeyes to Mack Pack tie points? Or maybe I should ask how many boom padeyes you are using. My sail drops in a second and a half and there is brief moment when I am glad all of that stress is spread around so many padeyes. I really would not want to reduce their number.
* As I said, I’m having a new sail and Stack Pack made. When describing it to the sailmaker he kept misunderstanding things. I finally took him out for a sail a couple of weeks ago and he came back a changed man. (And this guy makes sails for some of the top competitive sailboats in the world and then goes out and races them.) He has recognized that the guy who designed this Stack Pack actually turned the whole thing into an integrated system. Properly made and adjusted, it works seamlessly and he agrees that by molding to the sail as it does, the Stack Pack is actually giving back a bit of the lift that it would normally be stealing from the sail. I don’t think he was just pandering to me because I overheard him explaining the system to one of his employees and he seemed pretty impressed.
Also, I kept telling him about how the wide open Stack Pack (when not under power) makes a huge bucket to drop the sail into. But you should have seen his eyes pop when I let it go and the whole 670 SF came down in about a second and a half - neatly stowed and ready to return to the dock. I guess he’s used to crews of people clambering around on the cabintop, folding the sail as it is slowly lowered. He later said that he told his wife about our sail and she wants to know why they have an uncomfortable race boat and not a Nonsuch. 
He’s still a racer, but is getting old and tired. Considering the bad medical news I received yesterday, I think I’m going to start grooming him to take over my boat in a few years. I’ll probably be cured - again - but I don’t want to leave my wife with a boat to get rid of if it goes poorly.