For quick connects installed *AFTER* the switchover regulator, you will have to remove the BBQ regulator. As written previously, the previously reduced pressure after the onboard regulator does not work well with the BBQ's regulator which expects full tank pressure.
For a Weber Q type or a Coleman Roadtrip BBQ, here is a link to adapters which easily replace your BBQ regulator. They also have an adapter for the Blackstone Grill if you have it.
Clicky