Since I have a 2 vessel setup, I have played around with no sparge configurations, and see my best efficiency from mashing all the water at once. My old mash went like this:
mash with 1.75qts/lb, mash out, added water to my preboil volume(7.8 gal). Recirc 10 min, pump to kettle. Average 62% eff, malt conditioned crushed with a .22 gap.
New mash goes like this:
mash with full water volume(we'll say 9 gallons with grain loss), mash out, pump to bk
Average 70% eff, exact same procedure/crush