windage tray question

How mandatory is the windage tray in my build?

The build (73 dart full interior) being built for acceleration blasts.

I've purchased the kevco oil pan & related pick up assy. I do not have windage tray. Was hoping the magic design of the kevco oil pan would take care of my windage tray needs. My how to build sbm book is telling me different. Willing to work on other areas of build until this part is available to install.

What does it do?

Which one I purchase?