The Banks adapter is by far the superior method in my opionion. Looks like it belongs there, gives you the most routing options, and with the hose pointed up, encourages maximium oil drain back. Part number in the Parts Bin (tech article).
Suppose the air filter became restricted, dirt etc. could the added suction of the intake overcome the spring tension and pull the cdr closed then the crankcase pressure would build and push oil out weak seals and gaskets. Thoughts welcome.
Sorry I didn't make my original question clearer.