Alrighty, here we go:
First, the big page of Cyrillic doesn’t look like it’s going to be much help. All of the measurements in kilograms that are reasonably close to such a shroud mass are actually throw weights of smaller U.S. boosters. That is, there is no number on that page that might be the shroud mass in kilograms, and you don’t measure shroud mass in “tonnes” unless you’re very bad at building shrouds.
Secondly, I don’t think the payload canister you’re searching for was ever built. I’ve been reading the development history, and I don’t think it even has a name! “Polyus” numbers - if you can find them - might come closest to having what you want.
I’m going to weed through the mass breakdowns that are out there and see if I can derive a “missing piece” mass. Quite often you’ll see fueled masses for all stages, a payload mass, and then a total fueled mass which is slightly larger than the sum – this miscellaneous mystery mass is not all shroud (some of it is interstage hardware and so on) but gives you a very good first-order hack at the mass.
Failing that, I may try my hand at the size/mass comparison I suggested above, but that’s a fool’s errand unless you understand the engineering details of the shroud designs. It’s hard to know, for example, if a particular shroud used steel ribs instead of titanium ribs for budgetary reasons. Still, it might be worth a try.