If your not needing a remote grill hookup, you can just pick one of these up and install it between your tank valve and regulator.
To check for leaks, you turn on the tank to pressures the system and then shut it off.
Now you watch the gauge needle for 5 to 10 minutes. If it drops down to zero, there is a leak. The faster it drops the bigger the leak.
I've used one of these on my boat for ten years and tested for leaks every time I swapped tanks.
They cost under $15. and can stay in the system.