re: Red Eagle
found a repro of the cover and 15 black and white pages!
fewer panels per page than was typical of the time, but that helps explain how Thompson was able to do the whole book himself, if it's not some repurposed previous work.
checked the CBDB again: seems that half the book is in color but on glossy, cover stock...? odd.
also not clear if this book is all-original or reproduced from the Red Men two-pager from King Comics...
most striking, i thought, was how well and how quickly Thompson seems to have appropriated the tone of Prince Valiant -- AND Foster's LETTERING STYLE! -- for this strip (albeit with speech balloons). Valiant was a huge and immediate hit, but Foster stuck to a grid layout during the early months of the page, which began in Feb. 1937.
the first Red Men in CBDB was in King #14, with a cover date of May 1937 ...!!??!! that first installment might be somewhat different.
Foster and Thompson were also reading Raymond's Flash Gordon, which had a similarly mythic tone, so maybe there was something in the air and both cartoonists were developing these works independently...
but Thompson, wow! he already had it going on in 1938.