I'm guessing with the 144L you're sailing back forth, sometimes upwind & downwind and chasing a bit of speed when you get the urge, go out with the straps and start with the middle spot

If it feels uncomfortable, get comfortable by changing stance etc.
If you want to play around on the swells etc, go smaller and keep straps in.
Have a look at the boards of more experienced guys at your local.
I slalom sail in ocean, always have straps back and out, my new board has no options, straps are out

Ah poop, mkseven's quicker with the fingers and on the money