There are a few members here who either have raced Datsun 1000's in the past, or who are racing them now. If you drop them a line i'm sure they would be able to tell you their tales of woe or triumph, & how any front end problems were overcome.
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Come to think of it, I don't recall anyone mentioning spindle failure in any thread that I have read so far, so perhaps you are trying to address a problem that really isn't there.
The only problem that I don't really like about the Holden "heavy duty' spindles is the 'heavy' part.

Anyway, drop the racers a line to get the good oil, & you may just be able to save yourself some work