Wes,
thanks for your comments. I guess postwar float-type carburetors did have some significant improvement in respect of earlier ones. Unfortunately, there's still a lack of knowledge, IMO, about this not negligible aspect of WWII aerial fighting. Our discussion have at least raised some hint, like "well documented" Dutch complaints about D.XXI powerplant and mention about Russian pilots having similar problems. At same time, it seems that maneuvering so to avoid negative G cutout was second nature for period aviators - which looks logical - and perhaps explain why it's so hard to find such kind of comments. Nevertheless, I think would be interesting to have routinely more info - maybe extracted from relevant manuals - about fuel feed of each aircraft, its limits and features.
Cheers,
GB