I noticed there were still some missing rivets in the bottom fuselage which were too difficult at the moment or I was missing the right bucking bar.

First did some rivets in the top of the last bulkhead and then noticed this open hole underneath the stiffener. I had tried to set this rivet before and noticed that the hole was enlarged while drilling out.

I made a small doubler to solve this. It's so thight there that it's almost impossible to hold the little doubler while bucking so I used some masking tape to hold it.

Set the rivet and here's the result. Looks good.

 Also noticed I still had to set the rivet on the bottom of the F-726B angle on the back of the bellcrank channel.

I couldn't put the gun in the same direction as the other rivets so had to set this rivet using an offset rivet set and the bucking bar in between the two channels.
The rivet doesn't know what it's front are back is so it's just a cosmetic inconvenience.