tomtom is right, there is no consensus on this.
A few ride short lines, most ride their normal lines, and many ride a tad longer.
If wind is changing a lot, I ride 30 m lines, also on the really large wings. And when using a kite bigger than 10 m2 always 30 m lines.
But when I am normally powered, even with small kites 3.5 or 5 or 6 m2, I ride 26-27 m lines, ALWAYS.
Hate shorter lines, they dont give me the smooth fluid fast carves and turns I like, and they are way too on/off for my liking - not good (for me)
Others go as low as 15 m lines I can read here.
Nobody does this around here though, 22-24 is used often, and 25-27 m just as often.
Only the racers go 14-18 m lines here.
So as said, no consensus
PS: have noticed that many are using the main forum now, instead of the hydrofoil forum.
Maybe because foiling is getting so big they do this
Same thing has happened around here, some years ago it was a small niche sport in kiting, now the main (Danish) forum is used by foilers too instead of a specific foil forum, as we grow fast in numbers