Do you want TTL metering? AE operation? How likely are you to be using the 75 Summilux, 90 Summicron or 50 Noctilux? How likely are you to want to use the wider lenses?
Helen,

TTL Metering or AE is not necessary. I'm thinking wide to normal for lenses, but it would be nice to be able to use a 90mm.

Thanks!

Jim