I decided that part of the problem with the F-779 and F-711 riveting was the work was not being held securely enough. Did some research and tried several ways of clamping the work and riveting. The picture #1 looks messy, but I was able to get good rivets with this set up using the gun and tungsten bucking bar. Only had to drill out a couple. The bottom four were tried several times and the holes grew oversize.
Proceeded with riveting the F-779 and F-778 bottom skin to the bulkheads. Used the long back riveting set with Frances under the fuselage bucking.
Wrote to Van's and asked if I could use pulled rivets to substitute in the four bad holes on the F-711 bulkhead. Van's gave the OK to drill the holes to #30 and use Cherry Max CS3212-4-2 . I ordered some right away.