Will follow this as I have the same question. I tried to use one I found on Amazon for my GSI Selkirk 540 Camp Stove which was made for a Blackstone Tabletop Camper Grill, but the regulator wasn't compatible and it would only run with a very low flame.
Also, the brass portion that screws into the stove is a different shape than say a Coleman for example. The threads are the same, but it doesn't fit right with the same sort of seal.
I ended up going with a simple hose that has a 1 lb propane bottle male adapter that the existing brass regulator assembly can screw into. These are easy to find and it works exactly the same as it does with a 1 lb bottle screwed in.
I would love to find a proper adapter/regulator that I could use though, because the included brass one sticks out too far, even after I (carefully with the proper tools) bent it in for a 90-degree angle.