I am doing something and I am not sure if it is optimal.
I use the Braumeister 50L system. When making session beers (45-50G) I setup the mash with ~47 to 50 liters and use 11kg of malt.
After the mash I sparge between 18 and 24 liters at ~75 C to get to a total of 55 liters post boil (sometimes I mash overnight, then I have to sparge 24 liters as I lose extra liquid).
I sparge that amount of water fairly fast in 4 bulks (the pot I use takes 6 liters). Total time is about 30 minutes. I sparge into a big bucket and add it pre-boil. I lose some sugar but I am not too concerned about that as with that big amount of water, I should wash most of it out, I assume.
What do you guys think about that?