WOW! I do thank all of you for your prompt and thorough responses!!!
I think I hit gold here - this web site seems to be the virtual hide out of all the film and old camera junkies!
Thanks for all the info, I think I will try a Alk. replacement and see how it goes, perhaps checking it with a modern light meter as a reference (It will be mainly used for B&W print film, so I do have some latitude to play with). I am glad to hear that my choice of first rangefinder seems to be well supported by so many of you. I am also glad that Ms Nakamura's writing is as good factually as it is to read - I will keep an eye out for her name, a really, really good read!
And yes, I did go to the Kyle Cassidy page... and my sides still hurt. My wife and I sat there and read everything on his site, laughing our posteriors off well into the wee hours of the morning! The Leica story with Hemingway in it is especially priceless!!!

Thanks again,

Peter.