I know with straight surf leashes, it's recommend to have a leash about the same length of the board, which is how I've gone.

However, I'm thinking of getting a coiled leash for flat-water and downwinding.
I'm looking to get it from these Kiwis (see link below), as I've been impressed with the design and quality of their Waterman hydration pack which I've been using for a while now.

www.curvesurf.com.au/products/leash-sup-coil-stand-up-paddle-board-leash-australia

I've never had a coil leash before, so just wondering about the length to get. I'd be downwinding on a 12'6. I'm thinking to just get the 10' (which is the shortest they do).

Any advantage of getting a longer one?

What PT said.

I use an 8' Balin coil (ankle) on downwinders and flat water racing/training.
On DWs I was using a 10' half-coil but it would foul my fin whenever I fell off (probably due to something stupid I was doing) and I'd almost always forget to unfoul it getting back up again, it gave me the sh1ts. The 8' coil runs out plenty long enough on a 14 and doesn't ever get underfoot.

I think DJ uses a 9' or 10' half-coil but he's not clumsy like me. I certainly wouldn't go longer than 10' for DW, especially on a 12'6.

I have the ocean and earth half coil...........dont get that it hangs in the water on my 14'

Here's a few old posts about it...

Click here.. www.seabreeze.com.au/forums/Stand-Up-Paddle/SUP/New-Balin-leggie/?SearchTerms=Balin,leggie

DJ

www.seabreeze.com.au/forums/Stand-Up-Paddle/SUP/Coil-leggie-for-race-board/

www.seabreeze.com.au/forums/Stand-Up-Paddle/SUP/Do-I-need-a-SUP-specific-leash/

www.seabreeze.com.au/forums/Stand-Up-Paddle/SUP/Balin-ripoff/