I use a HERMS system to continuously recirculate through the mash, through a coil immersed in a thermostatically-controlled water bath and back into the mash tun. So, the mash tun valve is already wide open. I just turn off the pump to move the hose running back to the mash tun into a kettle and turn it back on. If I were not recirculating, I guess I would open it slowly to ensure the grain bed was set and maybe recirculate a gallon or so to ensure the wort runs clear.
I dump my sparge water into the mash tun and stir. The idea is to get good contact between the sparge water and the grain so the sugars can be rinsed/dissolved into the water. You re-establish the grain bed filter by recirculating the wort until it runs clear. I believe Denny uses a pitcher. He reports he only has to recirculate a couple of pitchers to get clear wort. I use my pump. I don't know what Denny paid for his pitcher. My pump cost about $140. It's entirely possible Denny saved a little money by using a pitcher.
Batch sparging is very simple and I typically get 75 - 80% brewhouse efficiency from it - depending on my mash schedule. I don't care much about efficiency, but there are so many threads on the subject I'll throw it out there for your consideration.
Denny Conn has brewed more beer than anyone I know of. He knows what he's talking about. Try batch sparging a couple of times on a simple recipe and see how you like it. I suspect you'll find it's worth any decrease in efficiency - and I doubt you'll see a decrease.