Milton Industries is a good source for pneumatic air chucks, metal tire valves, and tire valve extenders, metal valve caps. They can be purchased on amazon.
I've used the short, brass, air through extenders on my dually metal tire valves for the past 10 years (~ 100k miles) with no issues. Milton has 3/4" ones up to 5"
I prefer to use a 12" long dual head air chuck vs. the more standard 6". Makes it easier to hold the chuck against and seal to the valve stem.
I prefer the straight foot dual head air chuck (693 series, bottom) to the angled head style (690 series, top) for airing up the duals.