On these guns --
Just finished reading, en route to the Gold Coast, Wade Davis' extraordinary book Into the Silence: The Great War, Mallory, and the Conquest of Everest. Early in the book, interspersed with his story of the first efforts by Europeans to travel to Everest (late in the 19th & early in the 20th century), and the imagining/mythologizing of the mountain which followed, are terrifying accounts of the "Great War", and especially of the destructive force of these guns. The book is as much social history as a tale of mountaineering, and Davis' account of the industrialized slaughter of that war is sobering in the extreme, as we approach the centenary of the start of the war. Not a quick read, but a brilliant piece of work.
The book has some fine period photographs (from the British expeditions of 1921, 1922, and 1924), but I'd have liked to have seen more. You may find it interesting to do a comparison at some point in your project, Dan.
J.