Yep every G meter I have used for the last 30 years uses 1G as a datum.
I have the entire document (lots of maths), there are is no list in the document as to the equipment being used. The term "G" is standard aviation terminology though. The snippet below comes from a comment in the covering letter to the document discussing testing methods used versus the nature of the original problem of G cut out in unmodified aeroplanes. Again the G used is unambiguous to me. The phenomenon occurring at "0.1 to 0g"
I will look through the second RAE doc that deals with the devices being tested to overcome the cutout (not very well either according to that document) to see if their are any equipment details in there.
Edit. The second document equipment list makes no mention of the Type of G meter used either. It simply lists the specific fuel system in each of the aircraft tested.