I don't use my OEM BOV. I removed it and am only using the Blitz one. Also, I thought the screw was used to adjust how far the centerpiece can travel. If you take it all the way out you will create a vac-leak and trip your oxygen sensors so the check-engine light will come on.
As a side note, check your BOV every year. My check-engine light kept coming on because my center brass cylinder was getting "stuck" open more than it should. I tore the unit apart and cleaned it up and, bam--good as new, no more engine-light.