Jim,

I think you should use BOTH methods. One when the engine is apart, the other when it is finally back togather. This acts as a double check and helps insure that you have the correct numbers.

Jack,

No arguments with that. It's hard to fault a routine of double-checking before you call yourself done. Takes more time up front, but may save time in the end, plus you gain the peace of mind. "Measure twice, cut once."

If something's not measuring out like you expect it, find another way to measure it.