This is my first time digging into a Weber gasser and had to do a little research to figure out this fitting swap. Here's the info for the next person that comes along looking to do the same thing.
You need an 11/16th deep socket most likely to get the job done. I also used some thread pipe sealant because I had it around.
I do not know what type of sealant you used in your retrofit, but not all pipe thread compounds are intended for use with gas. For those who might do this in the future, make sure you are using a compound designed for the purpose.
Also, FWIW the "acme nut" is called a QCC1 fitting, with the reverse threaded male fitting called a POL fitting.