You and yellow rose could have a great discussion about all this because he believes that the main problem is the oil timing from when the oil leaves the saddle to when it hits the rod bearing.
I agree that the timing could have/has something to do with it. That and the direction the oil has to move through the crank vs. centrifugal forces. However, I've tried full groove bearings, cross drilling cranks, etc with zero benefits.
Another issue is the timing of the passage in the cam journal lining up with the block passages vs. where the crank is as far as the rod/piston being under a high load i.e. on the firing stroke. Does a 1/4" hole suddenly opening from the main saddle all the way to the head cause a quick drop in pressure just as the load on the rod bearing is greatest?