Beersmith (the brewing software I use) predicts 1.051 OG (for 5 gallons even) prior to the yeast pitch.
For extract brewing, boil-off does not really matter, just the total sugars and the volume.
Enjoy your witbier. I've got one finishing up its ferment in the basement right now.
[Ed. Yooper beat me to it. Trying to rub in the collapse of the Avs in game 4?