When I first built my system, one of my buddies said I'd need a grant, and I'd seen his on his system. I said I'd add one if I though I needed one. I have a keggle tun with a full SS false bottom, and mill at .032, and I have had just one stuck sparge, but not from pumping too fast, but rather from too sticky of a mash. I recirculate while I raise to mash out (direct fire), and just watch my pump speed carefully. By the time I'm transferring, I've got a nice clear wort, and a consistent flow. But I'd add a grant if I found I couldn't pump without getting a stuck sparge, for sure.
One of the simplest grants I ever saw was a used SS pot from the thrift store, with an inlet and an outlet drilled near the bottom on opposite sides. Just have to watch it, because it's easy to pump dry and then have to shut off the pump and reprime, and it's easy to overflow the grant if you're not watching.