The GM engineers who developed the PCV system for commercial vehicles had some very good reasons to design I the way they did. It works. Any attempt to outsmart the guys who got paid handsomely to develop that system by "smarter" hottrodders and hobbyists probably isn't going be very successful. It's easy to duplicate the factory setup, and the way the line from the road draft tube is routed isn't very important- - - -over the valve cover, in front of or behind it, and even under the oil pan shouldn't make much of a difference. The under the pan approach doesn't make sense to me, but that's just my opinion. Opinions are like "noses"- - - -everybody's got one, and some of them are pretty "smelly"!
Jerry