I get good efficiency with this method. 1.25 quarts per pound mash, then drain. Add 1 quart per pound (170F), stir, wait 5 minutes, start draining, when the liquid level is just over the grain bed start adding .75 quarts per pound hot water (185F) as in a fly sparge.
I use a round igloo with a false bottom and a mash pad. Mash pads are out of favor but I really like it. No voflauf and no partially open valves. I drain fast.