I was able to attach the remaining gussets up to the tailpost. I also started preparations to join the two sides. One first step is to fold the circular gusset around the longeron to join the cross members. I was able to fold one side only. I ran out of rivets. The kit seems to be short when it comes to rivets.
When the two sides come together at the tailpost there is interference between the sides. This is due to the longeron tube diameter being too large. The instructions are to anneal the tubes (heat them) then beat them into the right shape. So, I annealed the longerons at the tailpost with a torch. The heating was fine but when I beat the tube to reduce its diameter it split. Fortunately it is not a structural area. To keep the split from migrating with vibration I drilled a small stop hole.