I agree with Gene and withwannchev
A squirt of oil in each spark plug hole sounds like a good idea.
And priming the oil system with a drill and screw driver shank is mandatory in my opinion to fill the oil troughs once the engine is sitting upright in the vehicle and will stay that way.
I also agree that 5W-20 is the right weight of oil for break-in, and in fact in my opinion it is the right oil to keep using from then on as well.
The old dipper oiled Chevs lubricate best with light oils.
I do nearly the same thing wannchev does,
I change oil very soon after first starting.
Even when I buy a new car, I drive it home to the shop and change oil.
I would however use a high quality oil for ALL fills.
And as said by Gene and wannchev...
no slow idling!
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