Sidebar: one of my AVG friends was the late Ken Jernstedt, prewar USMC aviator who returned from the CBI and became a Republic test pilot. IIRC he said he was delegated to look at various bubble designs and chose the type that was selected. Don't think that's recorded anywhere though when the vile Fairchild took over Republic, all the T-boat material was dumped except for some X-job documents.
Incidentally: I received a review copy of Kleiner's "untold story" of the Flying Tigers. Have not placed a review yet, and frankly it's not very remarkable. Dan Ford's 1990s volume remains the ultimate treatment.