Continued the riveting of the horizontal stabilizer. I got a little overzealous and also the holes meant for the vertical stabilizer tie-in bracket. No worries they were easily removed with no damage, probably because they will be drilled to 3/16 anyways for AN3 bolts.
If you look carefully you will also see some size 5 rivets in the places where the roundness were gone after size 4 removal.