Drawing shows all the rivets are flush on the rear so I dimpled both plates. The rear plate to take the flush rivet and the front (A) plate to accempt B's dimple. I also take a few turns of the countersink tool in the dimples of the front plate that accepts the dimples.
After deburring, cleaning, and priming I rivetted the two halves together in 14 spots. Note I'm building a tri-gear 7A and so on rivet doesn't get put in and the tie down doesn't get located now. The plans say wait, the drawing suggest I can match drill the 8 holes in the tie down thru the bulkhead but rivet only four of them. But the plan clearly says wil be located later. So no problem to wait. I can always drill and rivet.
As an engineer I really hate trusting the plan more then the drawings. Because an engineer made the drawings.