Standard 4 line bar into adjustable Y bar.
1. Line Stopper ball (2 halves screw together)
2. Small Stainless steel ring
3.Small rubber band.
Place on the front line that does" NOT " flag out.
Screw stopper on front line at desired height.
Slide ring 'from tpp' over both front lines, down to stopper.
Tie ring with rubber band to the line on top of stopper ball.
When the kite is powered up, it wants to pull the lines apart - the ball stops the ring from dropping lower..
The rubber band is simple and lets you slide up or down if needed and grippy enough to stay in place. Replace the rubber band after a few months - simple.
Your flag out line works as normal.
If used with longer than standard lines, adjust the height so it keeps the correct shape of the kite.
I use it on my high Y Core Xr5 kite and slide one line out - for my Epic Screamers.
A bonus is that you can adjust slightly for higher for stronger winds to reduce flaring. It will turn a little faster ' at the lose of some wind range.
Most kites get Ugly when over powered so holding the leading edge more stable, can be a good thing - to a point, obviously.