I use 20m lines on my Nano 9m & 12m and love it. Similar profile kite, so called "Delta" shape.

Went back to 24m for a light wind session and the kite felt so unresponsive ... but it did help on water starts and trying to get on the wave a bit better.

But still prefer 20m lines.

If a bit too twitchy, try it on the narrow bar setting to slow it down.

Cheers
Rich

You gotta have the 37.5's for those light wind days though easily adds another 1.6knots to your kites low end.

Thanks for the info loco4olas.

And sir Rowdy. I'll be sure to get some 75's so I can get the sea breeze 2 hours before it gets to the coast.

Got a theory on this one…
I’ve ridden 15m lines before for freestyle and waves on a 05 slingshot back in the day. It was super quick and responsive – not great for wakestyle as it was too twitchy but kiteloops were insane.
However, I reckon lines in the 12-15m range would be perfect for unhooked waveriding ONLY IF you have the right size kite up. The kite will move faster to the edge of the window which means as soon there is any resistance perpendicular to the kite lines, it should shoot to the edge of the window. This means that you can actually complete a snap without getting pulled down the line 20m before setting up for your next turn (an obvious result when the kite flies further back in the window for longer). It also means that you have less power in the kite on the wave which means you rely on the wave more. In other words, although it is an advantage for those who want to throw the kite around, it’s probably more of an advantage for those that park and ride.
Buy some lines, grab mum’s sissors and try for yourself…