Fido, et al,
I don't recall, from the first time I put the engine together, that I had to pre-compress the spring to get the nut on. Hopefully, it won't be that long before I am reminded. I believe the geometry of the nut is, fundamentally, the same except there is no dished-out portion where the cotter pin fits in. SRM advises to make it so tight that it will never loosen. Regardless, I will also use some Loctite.
With regard to the nearly immeasurable end play, I ended up doing what I threatened, rather than buying a dial indicator. That is, I took 20 readings in each direction while using the digital caliper. I stabilized my measurement approach, always measuring to the same spot on the right-side journal face and keeping my hands as stable as possible while measuring to a precision-machined guide block laid across the oil-pump landing zone and the side opposite. Averaging the readings rendered a result of 0.0016" end play with a standard deviation around 0.0006". To me this was indication, enough, that I have it about right.
With regard to the tightness of the bearing to the crank, I have decided to leave it in place without adding Loctite. I had heated the bearing before fitting it to the crank in a cold garage. Though it wasn't extremely tight going on, it still had to be driven home. I don't expect the heating of the engine to result in the bearing becoming loose (due to expansion of the bearing race), as the crank will be at the same temperature, or nearly so, and crank and bearing race have the same coeeficient of expansion.
I suppose this is a lot of elementary mechanics to some of you and, as always, I appreciate more epert advice and opinions. Also, though it is a lot of chatter, it is more interesting, to me, than the next thing I must do. Work.
Richard