Elevator control horn problem RV-7A

[jdeas]

I had a problem on my left elevator with the fitting of the elevator horn.
The elevator horn had a ridge under the powdercoat that kept it from lying flat against the spar.
I ended up grinding off the powder coat and offending weld ridge in one or two areas until I felt the control horn could lay flat. I then zinc chrom?ed the horn and matched drilled.

I was very proud of my work until I inspected the match drilling I did. While the spar looked normal the E705 end rib attach holes (AN460AD4-4) were slightly oblong.
Where the rest of the holes measure .12, two of the holes in the rib are oblong .12-.15
So, what is the hole tolerance for AD4?s? If .15 is too large, what is the most practical option?

I am also wondering how people have attached E-705 to E-606PP. This is where the trim spar meets the inboard rib. The instructions call for machine countersink with the shop head on either side. Not only is the material a bit thin for countersinking but why use a flush rivet if it doesn?t matter what side is flush? (This is listed on page 6-10 5 th item from the bottom)

*Just got an email from vans on the last item. I guess the 705 to 606 is flush to reduce parts count. No technical reason, the flush rivets are already used in other areas.....

Thanks,
JD