Good work on the drill-out and re-rivets. I had to drill a few out myself, and I am not much farther ahead of you.
I noticed that you haven't notched the rear spar underneath the HS-411PP center bearing/hinge. On the plans, you will notice a hatched area right under that bearing where it instructs us to notch this part of the flange out (but not touching the HS-609PP reinforcement bars).
I had to go back and trim mine after I had riveted the rear spar together, so its not as nice and clean as I'd like, but I think it will be OK. I included some drilled holes for reliefs. You can see it on my blog:
http://theskunkwerx.com/rv7/dimpling-the-right-horizontal-stabilizer/
I just had to rough guess the length of the cuts based on the drawing and relation to the holes. It refers us to DWG 27A but I could not find any measurements there.
And here is a large photo before I cleaned it up a little:
https://theskunkwerx.com/wp-content/uploads/2016/11/IMG_0716.jpg
I also am not sure that is even correct to do this at this stage, but I went ahead and did it while the spar was easy to access.