This is my guess..... 65-70 lbs.
I think it's near impossible to make an accurate guess, there are many theories to calculate adult weight but in the end you just have to wait and see.
Our boy is almost 10 months and is over 60 lbs, we are expecting him to reach 75-80. His dad was very big, but his mother along the small side so I guess he will be somewhere in between.