If the pinch method doesn't work out for you, you can tune the LSN the way Ron Paris and many other does:

Most engine manufacturers recommend a specific setting for the idle-stop screw, and they’re usually well within the ballpark. For now, set the idlestop screw so that the engine will idle at a moderate rpm without stalling.
Bring the engine up to operating temperature by driving it for a few minutes. Now stop the car and listen to the engine’s idle speed. If the engine idles fast but then slows down in just a few seconds, the low-speed needle is probably set too rich. Lean the low-speed needle (by turning it clockwise in one-hour increments) until, after running a few more laps, the idle stays high for about twenty seconds or so when you stop the car. Once you’ve done this, use the idle-stop screw to make the final adjustment of the idle speed.

The 20 second idle is with approximate ˝ full tank.

Cheers