I tried the Wein cells once. Worked the meter in my OM-1 well… until I set the camera aside for a while. Next time I picked it up, the battery was dead.
Classic Cameras offers the MR9 Battery Adapter that allows the use of a 386 cell in place of the mercury PX13. I’ve found it works well, and 386 batteries are cheap. Better to think of the environment and avoid breaking laws, and convert to 386 cells. You can also have your meter recalibrated to use the 1.5v cell, but that’s more expensive than the adapter.