SUP seat or cushion (bottom only, no back) with 4 straps.

[SUP-Lurker]

i have this https://nixysports.com/products/monterey-touring-inflatable-paddle-board iSUP that has 4 D-rings to attach a seat in front of and behind the driver. Currently I have this seat https://nixysports.com/products/premium-adjustable-kayak-seat that only has 2 straps. the problem with that,  2 straps don't fix the seat at the exact position. In addition, I don't need the back. I just want to elevate myself (comfort, not getting wet).

The seat i have actually is very comfortable and i considered cutting off the back, and adding straps. but I fear I would butcher it up.

So, I'm looking for a cushion or bottom that has 4 attachment straps (2 front, 2 back) to attach of the 4 iSUP D-rings to be fixed in the exact position. Is there something like that? I looked all over, but most seats or cushions are made for kayaks and don't have straps or other attachment points.