druidh - I installed the crank the way RF recommended, with spacers in the following configuration:
NDS 1 mm Spindle spacers - 1 (factory installed on spindle)
NDS 2.5 mm BB Cup spacers - 1
DS 2.5 mm BB Cup spacers - 2
DS 1 mm Spindle spacers - 2 (factory installed on DS crank)
Per the RF pdf cited above, the crank clearance should be within 0.2 mm of each other.
So, I took my digital caliper and measured from the pedal side face of the crank to the seat tube. They were only 0.06 mm* off!
I then used the highly scientific and very repeatable method of sticking a finger between the crank arm and chain stay and determining that they are the same distance as well.
*I do realize that my measurement accuracy is probably not even that good. Even slightly different paint thickness on the two sides of the seat tube would affect the measurement this much, FFS. And I doubt that my caliper was held perfectly square, etc. Bottom line is that the crank is centered within a pretty small tolerance.