in my eyes and I think most measure just the length of flying lines as shown on the right of your picture.
To have a real comparison (and to come to the full system length) you have to add:
- Bar line length which is nearly always 1,0 m +/- 0,2 m
- sometimes pigtails (from 0,2 to 1,0 m Flysurfer)
(- and depending of kind of comparison maybe the length of mixer and bridle to the inner A point of the foil kite itself.)
But for behavior on short lines the kite itself with its span and turning ability will be more important than mixer and bridle length.
But I think your right that it matters if counting 1 m Bar line + around 0,5 m for pig tail.
I used my Chrono v1 15 m² with compared to a modern race kite low AR and span on 12 m of just flying lines with around 1,5 m of bar and pig tails and it felt possible but short. Than I added 1,5 m of extra flying lines and it felt very comfortable, nearly too long with 13,5 m flying line
. In comparison the 13 m² Sonic Race with its higher Span felt nearly shorter on the 15 m² flying lines I tried ... as far I remember.
So small changes of 1 m on short lines can matter a lot as also the kite does and therefore it is good to know how to measure and define to have the right comparison.
Happy cutting, splicing, boosting ...