I would not presoak the lifters. This could cause the lifters to act as a “solid” and prevent obtaining proper preload. What is very necessary is the priming of the entire engine’s oil system before starting up. This is done by turning the oil pump with a drill motor to force oil throughout the entire engine. I don't think it matters what kind of oil is used for start-up - any good 30 or 10W30 will be OK- and a new filter, of coarse. After the initial break in (30-40 minutes above 1500 rpm), replace the oil and filter with whatever kind your going to run on a regular basis. Any good prelube on the cam lobes, bottom of lifters, rod and main bearings will be fine.
