Windage Tray Height Location

If you look in the DC/MP bulletins or books you'll find a few paragraphs mentioning when the Chrysler tray is a help with a small block and when it was not. In all instances that it was recommended the openings needed to be increased. My recollection is that it was recommended as a power gain with relatively shallow pans.
There's some pics posted here or in the race forum showing I opened one up and installed expanded sheet metal like the milodon although back then I borrowed the idea from some other company's trays.

My understanding is the tray can do several things, one of which is act similar to a scraper.