The most important part of riveting the rear spar is to have it fastened down to your work table so it will not move around on you while you set the rivets.
After the rear spar is complete, I was able to cleco the remaining ribs and front spar together and rivet the ribs to the front spar. It is very important that you do not set any rivets to the rear spar as you will need to have access the fasten the skin to the ribs and front spar.
