The more I look at it, the more that is the direction I am leaning. Now I just have to measure a bunch of times and make sure it is right.
Here's the method I use:
Wrap the bars under the controls with a turn or two of electrical tape. The shiny black kind, not friction tape.
Position the controls where you want them.
Lightly clamp them down onto the tape, longer screws might be required, but you only need to tighten them enough to hold the control in place.
When you remove the control, the pin will have left an indent in the tape, that's where you drill the hole.