Lots of differing opinions in the past....What is the final verdict? Dyno guys? (not talking about crank scrapers here, I know they work). What have you guys seen and which types work best?

I'm using a combination of windage tray + crank scraper now. One thing I believe is the common windage trays don't have adequate drainage to help get the oil back into the sump.

With a standard OEM / MP style "short" tray, I added some vents as seen below.

However, I switched to a full-length style and went much further in terms of additional drain-back holes.

Tray on pan, plus scraper on tray on pan

Oil pressure steady up to 7200 RPM on engine dyno

I just put a summit tray in my hemi. I also added drain backs cause I’m using a scraper as well.

Louvers (like a small hood scoop, as shown above) are the preferred shape for drain-back, because they work strongly in one direction (down) and resist back-flow.
Simple holes flow equally in both directions.

IDK how to determine the exact height (below the crank, above the oil level). Ideally,

if one were to use a dimple die on the added round holes, would that resist back-flow some ?

The rotational pull of the crank & rods is pretty strong, so I've always adhered to the directional louver deal, which I open up a bit.
Crank scraper helps with pretty much anything you do.
Dimple-die on the round holes should help them act one-way, but a bunch of small round holes doesn't seem as effective, though they will obviously drain.
Easy enough to visualize the pan environment by rapidly stirring soup, though there's a bit more going on (pistons pumping)...

Definitely.
Best done with a tool shaped as a radius, from above, the larger the better. Th edges should point down if possible.

Round holes' area doesn't control the flow rate, since the edges are always a restriction (perhaps .020"). Bigger holes flow more in proportion to their area.

Do windage trays really work? How effective are they really? It just seems to me the tray would hold the oil right under the crank and cause more problems than they are worth. I never used one in my small blocks, but i do have one in my current 511 because i was told i needed it. I'm contemplating using one in the 572 Hemi.

Then there's the built-in tray/baffle combo...

I was told by one of the Mopar drag seminar engineers that Mopar had found a 5 HP increase on the 1968 383 magnum and 8 HP increase on the street Hemi and 440 magnum 375 HP 1968 motors while developing them in 1967 for both NASCAR and drag racing

I put a tray in a 79 360 truck during a rear main seal change and could feel the difference right away.

The scraper and a tray do basicly the same job. The scraper is better at removing the oil clinging to the crank. Your talking .060" clearance to rotating parts vs inches. The tray can't get close enough to do that. The tray does keep the rotating oil and crank action from upsetting the oil in the pan. Heck I use a hand fitted scraper, directional screen in the pan, multiple baffles, trap doors, and a swinging pick up.
Doug

Those scrapers are nice. To bad I never received the one I ordered a year ago.

Call Kevin. I found him pretty easy to deal with.
Doug

That is who I talked with. Easy to talk with... Never received what I ordered...

kind of what i had in mind with the dimple die used on the holes.
how does that setup work for you ?

It took me a couple of "reminder" calls to get one of the two I have. Like the product, but time to deliver was... unpredictable.