I use these adapters in several older cameras and meters. They are a simple solution and since the Z-A batteries give you closer to the proper voltage and discharge curve of the original Mercury batteries.
BTW, I just watch for the local Walgreens pharmacy to have hearing aid batteries on sale and stock up. Much cheaper than Wein Cells and I get about the same life from either. And f I forget to remove a battery and it dies, you don't get the normal battery corrosion problem.