Guessing your lean body weight is a tad difficult. Being at around 18% bodyfat and 193.5 lbs I would guess my lean body weight is 172 considering a good 15-20 lbs of that 34 lbs is not all fat, there's organs, brain and bones to consider, but I don't always make it to 175g of protein, sometimes 150 and sometimes 190. Which is good because I can be sure my lean weight is somewhere in there.