Thanks a lot for your input! I think I will give it a try because this model is like new with a counter of 015 - hard to find these days. If worst comes to worst I can always offer it for sale here
nworth: I'm a bit envious about your location! Geez, I wish I could spend a few weeks in your area...
BTW, just by coincidence I've discovered that you can use the right angle finder and all viewfinder accessories of a Nikon FE2 on the Fuji GW690 III as well! This makes shots close to the ground a lot easier.
The idea with the viewfinder of a Bessa is appealing. I've already contacted a dealer in Europe - he offers a brand new 40mm viewfinder for 149 Euros.
Again, thank you very much for your help.