OK, done some work and measuring. First I've put the bearings in place. (and no, the clutch side bearing wasn't super tight and in my opinion is at risk of moving)
The overall distance between bearings would be 57.30mm. The crank is 55.92mm (is within limits). That leaves a gap to fill of 1.38mm.

The existing shim on the clutch end is 0.6mm.
The shim for the other side can not be bigger than 0.78mm.
But being not completely sure I guess I will try to find 0.6mm shim stock and make one to fit.
Does this sound like the way to go or am I missing something here?

I am fairly certain the factory spec for the dimensions between the bearings is 56mm +.05 -.010  Very hard to measure that dimension.

I don't remember you mentioning you had any shims?  It's very common to only have a shim on the clutch side. Does not mean you are "missing" a shim.  The parts manual designation "U.R." means "use as required".

If it has shims on one or both sides they are always thin.  Later models had no shims (the very next model year). 

If it was mine, I'd put it together only with the shim you have.  Adding a thick shim might be a mistake.

Install crank into clutch bearing and tighten nut.  Use crank puller to pull crank into ignition bearing when assembling cases. Done.



 

I was not fully awake when I responded this morning...  not unusual. 

I don't know why I wrote "adding a thick shim"....  I meant to say "Adding a SECOND shim might be a mistake?"

"I was not fully awake when I responded this morning...  not unusual."

I have to keep on telling myself NOT to post any replies until after I've had my second coffee of the morning!