Nice work. I can't see the bottom of the 4 in box tubing, but I would recommend you beef up the area behind the ripper, on the bottom, so when you grab a big rock, the ripper does not rip out some of the 4 in box steel. You have enough shank there that it could happen.
I just bought one for $775 and can't wait to get it up to camp and try it out saturday. Would have been nice if you had a video of grading the driveway. Guess I will have to shoot something for U-tube this weekend.