Sorry, but the old catalogs available to me don't give any bullet or powder weights nor ballistics. I assume the American loads listed were merely the then (1908 – 1910) Winchester factory loads, the Uttendoerfer (later RWS) one being merely a copy of the W-W blackpowder load. It's your turn to find out if the Winchester hv load was available then.
Both blackgame and capercillie cocks were once hunted here in Germany during the courting season. Blackgame was most often shot from blinds, as this species prefers treeless, open heather and mosses. Displaying capercaillies were stalked and shot out of the tree. Such stalking was an art, described her: https://en.wikipedia.org/wiki/Western_capercaillie In both cases ranges were short, 20 to 40 yards. Due to changes in environment both species are now on the brink of extinction in Germany, not hunted any more for about 50 years.
For use on roebuck and any other hoofed game the .32-20 is outlawed in Germany since 1934, as it does not meet the minimum requirements: energy 1000 Joule at 100 meters, all other min 6.5mm = .25" bullet and 2000 Joule at 100 m.