Just for the record, as you guys are asking:
Sure, today's Poland was not a part of FSU formally. Major parts of pre-WWII Poland were incorporated directly into Soviet Union, the fact is sometimes forgotten, same as with Poland landing on a piece formerly belonging to German people. We here were "only" occupied by Soviets for 40-something years after Allies and Stalin have settled in Yalta. Puppet government, not much reparations paid, some loans still left to be paid, disaster after disaster. I wanted to explain my situation as easily, as possible, not going into politics and history. Warsaw Pact, or "behind the Iron Curtain" are the correct expressions here. If there's a moderator lurking, please change the phrase "it's FSU territory" into something like "it's almost like a part of FSU", so that there's no doubt.

So I've got my hands on Zorki C (or rather S) "Festival" edition, with collapsible Industar-22. Working, in good condition, no light leaks, has no major issues, it doesn't even scratch the film as badly, as I'd expect . The lens, well, it's not brilliant, but it collapses. Looks like it was used properly and heavily, but it's holding really well.

I've been able to make a single test roll out of the three rangefinders: Kiev 4AM with Helios 103, Zorki C with Industar 22 and Minolta Hi-Matic CS with it's fixed lens (38mm Rokkor, possibly Tessar-ish). Looks like every one is a different beast. I still have to make some prints out of those, for now I've only scanned it poorly, so there's little I can say about image quality, apart from the fact, that Minolta looks a bit underexposed (or maybe it's just me to like to have some extra detail in shadows), but it saved at least one shot.
Minolta is small and adorably pocketable, but I have serious doubts with it's robustness and I still don't like to depend on this kind of light metering.
Kiev has some excellence factor to it, but otherwise it's clunky and has some loose moments. Maybe it's creme de la creme of FSU rangefinders... Zorki is really what I expect a camera should be for what I do - that's pretty much "sketching", for serious work I have Pentax system with decent SLR and cheap DSLR.

Just for the record, Moskva 5 also worked without much trouble. Just as expected - slow times need to be taken care of. And I still have to make some prints out of that too (the negatives look great, but it doesn't mean much).
If I'm looking for a good viewfinder in FSU rangefinder, I guess "auxiliary" is the right answer.