I brewed it today. I originally decided to brew a vaguely out-of-style bitter featuring glacier and domestic tettnanger. The plan was to hit about 1.044 with a 152 mash temperature, get the bitterness from Glacier (an excellent bittering hop for bitters, IME), and FWH with an ounce of the Domestic Tettnanger, then drop a full ounce each of Glacier and US Tettnanger at flameout for a more robust hop character (and because the glacier just smelled so good while I was measuring out the bittering hops). Everything went fine, except that I forgot my hydrometer (I brewed this while visiting my mom for the day), so I couldn't check the pre-boil gravity, and I accidentally boiled off a 1/2 gallon more than planned. And when I came home, the gravity read 1.050. I somehow got a 4% efficiency boost on top of the extra evaporated 1/2 gallon. So I have a fairly hoppy 1.050 bitter with 37 calculated IBUs. ESB I suppose. I may add some water to the fermenter tonight to drop it down to 1.044-1.046, but probably not.