Hi Bramber,
Personally, I used to prefer 20m lines for kite looping as opposed to 24m. A 2m difference is barely noticeable, going to 4m is noticeable. Kite is much more direct and loops lower giving a good hard yank.
You've most likely seen many of the Core kiteloops in ads, these are usually on around 12-13m lines. This is proper gnarly for loops, but takes too much away from the general riding ease and you need to be super lit.
DM