I did a test run of this pump during a sparge and let me tell you: The manifold design is the key. The fact that I used such small holes turned out to be one of the best decisions throughout the whole system. During the vorlauf process, I got NO grains whatsoever. I went ahead and transferred the wort to the Brew Kettle with no issues and no grain pieces.
From what I have read, these pumps do NOT like particles, so I tried this before purchasing the secondary pump. This test successful, I have the second pump in place.