The OP seems to be concentrating on the M versions of these cameras. They have mechanical shutters and only need the batteries for TTL metering, so as long as he can get close enough on the exposure with his brain or an external light meter, his cameras will be ready to go.
Originally Posted by elekm
I'd have an R3M myself if they'd introduced it with the original R3A, but I can't complain. The batteries in the C/V Bessas are easy to find, and are also used in my SLRs, so I order some of the best over the internet in quantity at a huge discount over local stores, and always have spares in all my camera bags.