I got my nerve up to drill the oh-so-critical pushrod attach holes in the elevator horns today. It was one tenth as stressful as I figured it would be.
First, I drilled the #12 hole through the left horn, which is my forward-most horn. I did this on the workbench to make sure it was perfectly straight. Then I reattached the left elevator.
Next, I very securely clamped the elevators in trail and measured everything again, just to make sure. Then I measured the distance between the horns and cut a small block of hardwood that would fit perfectly between them. I drilled a #12 hole though the wood block with a drill press, then positioned it between the horns and clamped it. Then I simply drilled though the block and made a perfect, matching hole in the right horn. Worked great.
Next, I attached the elevator pushrods from back to front, making sure the control sticks were vertical. I had to do a bit of trimming along the edge of one hole though a fuselage bulkhead in order for the pushrod to clear sufficiently. At long last, I was able to move the sticks and feel the glassy-smooth elevator control, and watch the control surfaces move! Cool! Too bad it'll all have to come apart for painting soon. Oh well.