Well I beleive the answer to your velocity question can best be answered by looking at the basic recommendations from Chrysler and or Larry Athertons recommendations. The Chrysler recommendation is to cut the flow to all the lifters and to plug the end of the passenger galley. This reduces the amount of system leakage and therefore slows the oil speed effectively increasing
The pressure at the bearings.
The Larry Atherton crossover tube was designed with wet lifters in mind. But because of the way the oil travels to the drivers side combined with the leakage at the lifters and again with a high volume pump to offset all that leakage, you end up with a speed issue at number four main.
The crossover tube if done correctly, is designed to create a big leak or diversion just before number four main so that the speed of the oil is now slower as it passes by number four, allowing it to make the turn.
As you said in your previous answer, the bearings and rods consume oil, they leak. That is why an engine oil system is not the same as say your sealed brake system. It is not closed.