We had to take the elevator off and adjust screws no less than 15 times, perhaps more.
Ultimately we had to weld fill and re-drill one of our horns.
You might be able to just adust the length of your screws to get it to even out.
[edited, see rvbuilder2002's reply below]
Also, those horns can't be replaced easily (or at all really). Lots of builders have issues in this area, it's common.
Edit: If you do have to re-drill the holes, it's painless, cheap, and fast to get them filled by a welder. I put it off for weeks thinking it would be a hassle, took about 5 minutes, you can't even tell there was a hole there before.
Edit 2: This is the step where I learned that drilling steel requires patience, very low rpm, and a lot of pressure. A few bits were lost during this endeavor, but their legacy lives on