Any issues with just venting both valve covers to a vented catch can via -10 hoses. And blocking the valley port?
650rwhp?
I think this would have been covered in the original post, but if you essentially vent to atmosphere through a filtered can, then you are not actually evacuating the crankcase with vacuum, therefore you will always have high levels of corrosive combustion byproducts in the engine. You'll have less efficient ring seal, slightly lower MPG efficiency, more highly contaminated oil (and all that goes with that), increased corrosion internally on most all metal parts, and more pollution into atmosphere. Basically, it's the least-best option with all of the negatives and none of the positives, other than not blowing out gaskets.
Applying vacuum to the crankcase under low-load conditions (ie 95% of an engine's life) through a PCV system is really a win in every way. The cost and weight of a properly routed catch-can and PCV system is effectively negligible. To take that cost and open-vent is almost tragically missing the point, IMHO.