Honestly kitexpert you contradict your name at every turn. I often don't reply to you because well what they say about arguing with an idiot and all.
How can adjusting Z work when it's B and C that have shrunk? Well if you had read everything I had written that is not what I said. You would need to adjust BC and Z to get everything back to normal. Adjusting Z alone though can return the camber to normal though ( yes I know you believe you can't change camber with bridle tension "calm down"
). Adjusting BC has with it the same problems of Z both won't correct the AB depower limit alone. If a kite was designed to have sufficient slack from the start on B that "any" amount of shrink wouldn't see it go tight, then adjusting BC or Z alone could be used. But I have never seen such a kite even though it would seem modern kites that can fly solely on A could be designed like that.
Replacing pulley lines well before wear would require seems well stupid. Factor in NEW pulley lines can be shrunk close to 10% and shrink is a continual problem, that after 1hour of use "technically" an adjustment could be used then why not have an adjustment?, either on the pulley line or on BC and or Z.
As to the range of mixers... here your lack of understanding shines through. Well you will find the 1meter C pulley line on most flysurfers gives roughly 1m up and 1m down. From the 1m up down to about level is the normal flying range, the 1m down is more advanced flying, landing and relaunch or reverse flying. What you seem to stumble past is a mixer needs to do a few more things than are simply labelled as "AoA changes", the same as a kite needs to do a few more things than are simply labelled as "lift". You will find a bar is quite capable of having a trim range of 1m or even a bit more, and with the manual use of hands on lines like in relaunch another meter is close near achieved. As to whether 2ms of range is needed on foils kites? Well on the larger 21+ sizes that is perhaps a bit short, but on a smaller 6m then 1/2 to 2/3 of that would be enough. I think manufacture, design and support dictates a standard mixer size.
Porosity can induce instability, can be countered a bit with mixer. But also there is performance loss I guess from increased drag so overall there is no real win there. A punctured tire you can drive slow but best to patch it up.
I don't know, I've been working, designing, building (incl. mixers, many different kinds of them) and using depowerable foil kites for over 15 years now (I still occasionally do) and never I've had any special problems with speed systems or bridles, I mean nothing that would make me think there is something I don't understand. But I must say when I'm reading your posts foilholio I quite often find it hard to follow what do you mean.
1) Yes, you can adjust if there is possibility to do so and you take care of all line rows which are affected. Length of pulley line is not so critical as long as it isn't too short. Like Regis wrote this general shortening should be compensated on flying lines also (or making A shorter too).
2)Badly shrinked pulley lines which I've seen are also more or less worn out. It is a cheap line, not worth playing with.
3)These "advanced flying" things are possible because pulley lines have some practical length. 1m range on C is much more than any (available) kite or depower line length (sheeting range) allows. Relaunch (LE down) happens when back lines are pulled, other line rows don't matter that much as long as they are pulled less.
Your opinions on line lengths ("1m up and 1m down", "2ms range" etc.) are those hard to understand things. Only biggest kites benefit long sheeting ranges, and because modern big foil kites have high AR (relatively short chord) it isn't that relevant even for them.
I suggest to keep different component adjustments away from each other as long as possible. Then it remains possible to follow and isolate changes and fix them more at where they exist. FS mixer adjustment is ok though, but when it is used to correct bridle line changes results are less than perfect.
For me adjusting kite is not difficult because I feel and and see what should be done. But if you have less experience and read instructions from here it can be overwhelming task. Endless bridle/mixer tweaking is 99% nonsense.