I just got back yesterday from a hand gun hunt for them in Arizona and while it was cold this year we had a lot of fun.  As far as size I doubt that you can go with the size of the tusk.  I have killed quite a few of them and they all range from short ones to long ones not to mention broken ones.  Arizona and I believe New Mexico consider them a game animal while Texas classifies them as a varmet so there would be no record keeping for the ones from Texas.  Arizona will measure the head from the snout to the back of the head in inches down to the 1/16 th for their record books.  As far as weight size the largest one that I have killed was the first one that I got and it went around 65lbs on the hoof which is a very large one.  I also have seen one other one alive that looked like a regular pig.   He was dragging his bellie on the ground as he walked.  It was too bad that I had already filled my tag that year or else I would of known for sure how much he weighed.