The Clymer and Haynes manuals are good general guides, but if there is something that is R65 specific, chances are that it won't be mentioned.
I have the BMW shop manual, and this is written with the intent, that you have been formally factory trained to repair BMW motorcycles.
A lot of cautions and information that would help a novice prevent some costly mistakes, are ommited, as you are already supposed to know this general information.
So there is no 'best' manual out there, all of them contain errors, even the factory manual.
I would suggest, that if you get to a point and have a question that can't be answered by the manual, stop and make a posting here, someone will usually make a posting in a day or so .