Just admiring the beautiful tail assembly in my garage and noticed an error. The pull rivets on the close out tabs of the left trim tab were sitting quite proud. As in, I must have not dimpled them. I drilled out the rivets and sure enough no dimples. Not sure how I missed that step.
Had to drill out about 6 of the top skin to spar rivets on each side so that I could pull the skin back enough to dimple them. Also had to separate the inboard foam rib from the skin. I used a razor saw to slice through it. I will still provide the compression support of the skin and it is close enough to the end that it should be ok.
Got the holes dimpled with combination of squeezer and tight quarters die. Reinstalled the countersunk pull rivets and reinstalled the spar rivets.
All fixed. Glad I caught that.