Not sure what other bomber might have used a 4 blade ham standard, perhaps the B-26 Marauder? Most of the other R 2800 installations used three blade props, an exception being the F4U-4/5/7 and P47 series. The kind of stuff I need to look up.... to be sure.
Before the B-29 and R-3350 most of the heavy iron (b-17-B24) ran three blade units on the nominally 1200 hp class engines as did the Wildcat, SBD, Beef-ah-low etc. The electric Curtiss units could be troublesome, but at least could be feathered even if the engine was out of oil.
Excited to see all the latest developments.