The answer is... it depends. Some of us masterbatch at a 1:1 water:lye ratio, or a 50% lye solution. That allows us to have additional liquid that we can use when soaping to dissolve things like salt, sugar, citric acid/sodium citrate, etc.
But if you don't need or want to dissolve any additives, you can masterbatch your lye solution at the exact ratio you intend to use it. For example, your post mentioned using a 2:1 water:lye ratio (33% lye solution). You can premake a 33% solution rather than a 50% solution, and then yes, you would simply pour out the combined weight of water + lye.
Better yet, you can use the SoapmakingFriend calculator, and use the masterbatch lye function. That allows me to make a 50% lye solution masterbatch, and not have to do any math to figure out how much additional water I need to make the 40% solution that is my normal go-to. The calculator figures that out for me, and gives me one figure for my MB solution, and another figure for additional water (which I use to dissolve my additives). Check it out - it is really an awesome tool!