How to lock an SUP to Thule roof racks?

I just bought a used 9’6" Pau Hana Oahu SUP and my existing locks that I use for my kayaks and solo canoes don’t for this short & wide SUP.

There aren’t any attachment points on the board and the loops on my kayak Lasso Lock are to small and my pull-tite cable lock that I use on my canoes is too short.

What do you suggest?

This is my first SUP. I have multiple solo canoes and kayaks.

Thanks.

One solution is to use a fin-box lock, the plastic ones are https://www.paddlingparadise.com/fin-box-lock.htmlpretty cheap and probably would just prevent a causual pick up type thief. You can buy them made out of steel or aluminum. I made my own from plates of brass when I had access to a metal shop. Here is an example … it looks OK but I have no experience with this brand.

https://www.paddlingparadise.com/fin-box-lock.html

How about a Lasso Lock?
https://www.rei.com/product/752676/lasso-kayak-security-lock-ii-for-sup-sit-on-top-and-tandem-kayaks

Thanks,
I’ll probably buy a fin box lock from Pau Hanu, that’s what they suggested. Only $18, IIRC.

The Lasso Lock would have the benefit of being usable with the cover on the board, but I’m not sure if my board tapers out enough in the middle to keep the board from sliding out of the loops. My kayak Lasso Lock loops just fell off of the ends when I tried to snug it up - those loops are much too small.