When I get my ph right, I get 70% doing a double batch sparge, usng 1.5 to 1.75 quarts per lb for the mash, crushing with a JSM Malt Mill and doing a 75 min sacc rest. My AG brew day takes 4 hours by the way
Anyway, I am happy with 70 % and don't want to "chase" efficiency but as a tweak am...