I think you can use the weber q 20lb adapter hose as an off the shelf option
Yep, there is a generic hose that several manufacturers make that adapts from the 16 oz cylinder threads to the OPD valve that the bigger tanks have.
I have a Kenmore tabletop gasser and use one for it.
For a Performer the 5 gallon (20 lb) tank is overkill.
I would look for a still-certified, used 1 gallon or 2-1/2 gallon tank on CL.
I wouldn't try to buy those small sizes new...way over-priced.
I bought a "Schnozzle" and am going to try re-filling the little green tanks this summer.
I can't recommend that until I try it myself...some can't get it to work.