Getting the proper grain to water ratio is important.. I can't remember the exact effect, but if I remember right, too thick, and you risk running a poor efficiency, and too high and you risk ruining conversion from starch to sugar.
From my understanding when people talk about no sparge, just means they mash enough grain at the right grain:water ratio to come out with their full pre-boil volume.
On Deck: Chav Irish Red
Pipe Dreams: Chai Porter
Primary #1: Empty
Primary #2: Empty
Primary #3: Imperial Oatmeal Stout
Bottle Conditioning/Drinking: Brown Porter, Pale blonde session ale