It just so happens I stumbled across a
page on the Flight Test Historical Foundation website the other day that is all about the pressure suits in their collection. While it's not exactly what you're looking for, the level of detail suggests to me that someone there might be an expert on the subject who could answer your question.
A search of DTIC also produced this detail:
Agnes S. Burt wrote:
A total of 22 Berger Bros. pneumatic gradient pressure suits and 22 hydraulic Franks flying suits were flight tested by 26 pilots of the 9th Air Force in P-47 and P-51 aircraft. Complete visual protection was obtained with both suits.
(Source: Agnes S. Burt, "
Annotated Bibliography on the Physiological Effects of Acceleration in Aircraft" (Pensacola, Florida: Naval Aerospace Medical Research Lab, 1 September 1945), 11.)
So, I would try searching for Berger Brothers and Franks. If you could find a patent, that might contain some information.
It looks like the book
Combat Flying Equipment by C. G. Sweeting has much of the information you seek. For example, it states:
C. G. Sweeting wrote:
Twenty-two of the Berger Brothers prototype GPS outfits, along with equipment for the aircraft, were taken to the Eighth and Ninth Air Forces in England in December 1943, by Capt. George L. Maison, MC, Chief of the Acceleration Unit of the Aero Medical Laboratory.
(Source: C. G. Sweeting,
Combat Flying Equipment: U.S. Army Aviators’ Personal Equipment, 1917-1945 (Shrewsbury: Airlife, 1989), 154.)
(As an aside, I tried searching "George L. Maison" and discovered he also invented the asthma inhaler!
[1])
It also quotes Chuck Yeager as stating:
Chuck Yeager via C. G. Sweeting wrote:
We were equipped with anti-G-suits after invasion, about 1944.
(Source: C. G. Sweeting,
Combat Flying Equipment: U.S. Army Aviators’ Personal Equipment, 1917-1945 (Shrewsbury: Airlife, 1989), 145.)
However, note that the first G-suits were actually deployed by the British:
C. G. Sweeting wrote:
The first use of an anti-G-suit in combat occurred in November 1942, when fighter pilots of the British Navy Fleet Air Arm used the Mark II FFS in action over Oran, Algeria.
(Source: C. G. Sweeting,
Combat Flying Equipment: U.S. Army Aviators’ Personal Equipment, 1917-1945 (Shrewsbury: Airlife, 1989), 151.)