I understand that it is the general consensus to measure OG before pitching your yeast, but does that also mean measuring it before you add your excess water? I had 3 and a half gallons of wort that measured 1.100 OG, I measured this before I pitched my yeast and added it to 2 gal of water. Obviously the water would dilute it, but by how much? Should I use that number for my OG?