I just recently installed the IT system in my balls, so this will be my first trip to the open championships with this system.  I was just wondering how it works going through weigh in with an interchangeable thumb system.  Do they take your thumb and move it from ball to ball as they weigh?  I would assume this is what would happen.  I can't believe they would expect you to have a thumb slug in every ball right? Or does the ball need to be legal with both a slug or without a slug? I realize a drilled slug doesn't weight that much, but it could be enough to change the static weights.

I've had the Vise IT system the past two years in my trips to Nationals, and in both cases I just let the weigh-in staff know I had the interchangeable thumbs, so I needed to pop the thumb slug out of each ball after weighing it to put it in the next one. This worked just fine and every ball checked out OK, and I didn't hold up the line any longer than anybody else did.

I had seven balls with the IT system and three inserts.  I rotated them as each was weighed in.