I have no need, and am far too critical (some - ok, a lot of friends - would say persnickity) to rely on guesswork. I can't speak about the adapter until I get it, but I'm pretty happy with Wein cells and, for that matter, have handheld meters that use modern batteries. I've always carried my Luna Pro SBC with my Yashicamat 124 for example, even though my Yashica meter does actually work. I use a spot meter for large format. The closest I come to guess work is to set a manual camera for prevailing conditions so I can shoot without additional metering as long as lighting is pretty consistent or "add a stop because that's kind of shady" which I suppose is "by eye" but it's always based on starting with a meter reading for me. As you say, YMMV. If the adapter doesn't work, I'm actually happy with the Wein cells.
You do have to be careful though. The "diode" adapter I found on Amazon had reviews saying, and photos to confirm, that it was really just a piece of metal falsely advertised. The Kanto adapters from Japan appear to be the real deal.
A $7 battery that usually lasts me at least a year is fine though. When I tried to post the link it didn't work for some reason, but Weincell at $6.98 with free Prime shipping from Amazon.