Figuring a quart and a liter are about the same, a stiff mash is about 1 qt/lb which I use on most bigger beers due to mash tun space. On a smaller beer I'll do 1.5 qts/lb. 2qt/lb, which you are doing is a thinner mash but can work. I wouldn't go any thinner, though.
With an all barley beer you can use a thicker mash like 1qt/lb. If you have lots of wheat or adjuncts then a thicker mash is necessary. I have *heard* but never verified that a thinner mash yields a more fermentable beer. Perhaps a more seasoned AG brewer can chime in...