Both beads are the same, save for the height. As I recall 10 thou made 2" difference at 100 yards, but that would depend on the sight radius; (read the barrel length).

Percival was "Pops" in the Hemingway accounts. It's been a few years since I read them. I'd imagine that what he did was the right thing to do for his times. Cars on safari were probably a somewhat new thing, (the book shows a picture of a lion being loaded in the back of one of the wooden-spoke wheeled vehicles). I guess they got a bad wrap in the years that followed and so the rules changed.

Re the options being added together, maybe. I don't think the custom department at the Steyr Works was ever short of work. So there would be plenty of commissions for this optional extra or that. The take-down was known as the "English model", (in Steyr's 1930's catalogs). Ballie-Grohman was also a writer whose books you might be interested in. He was fanatical about hunting chamois and owned a large hunting preserve with them in.