As Phil and others suggest, for Oktavas, it REALLY helps to hear the exact microphone you're going to buy. Or buy from The Sound Room, which in the past (and probably still currently) had a good track record of actually rejecting (and not selling) individual mics with serious flaws. That's where my MK-012s came from, and they seem pretty good for the breed. https://sound-room.com/home
For you, living way away from everything, maybe see if a mixer or two will be visiting the Main Workshops in Rockport. Or maybe trek down to Boston and buy lunch for a couple local mixers (there are some good ones in that town). Or head down to NYC and visit Gotham Sound (and perhaps a couple friendly/hungry mixers), and give a bunch of mics a listen.
I've rented/demoed mics before buying; good dealers can help arrange that...sometimes the rental fee can be applied towards the purchase price. But you know, I've bought microphones without first hearing them. Based on my experience with other mics, the opinions of people I trust (including many here), and the ability to return a mic if it really isn't working for me, that works. Also, I just do small jobs. Unlike a bunch of people here, I don't own and buy tons of mics. There's no local location-audio dealer here (San Francisco bay area), and I'm dealing with it.
For the better mics, there's consistency from unit to unit...also note that for these mics, specialty dealers such at Gotham, Trew, and others offer basically the same prices as the box stores such as B&H, Sweetwater, etc...and the specialty dealers usually offer expertise in our arcane field. (Sorry if this is all obvious).