Where can I find an adapter for a 2007 VW Rabbit Fuel Rail Bleeder Valve?

I just changed my fuel filter and am about to change my fuel injectors. I’ve gotten a significant amount of air to flush out of the fuel lines, and I would like to purge it using my fuel pressure tester to avoid damage before attempting to start the car for the first time. I am surprised but I cannot find any adapters to fit my fuel tester (which has 2 adapters, to this rail. The Bently manual just references some $1500 VW fuel tester and I cannot find anyone selling an adapter. Where can I get this part or even the specifications for such a part?

Ideally, it would be an adapter to the common GM, Ford size.