I use the slightly angled part of the drop just below the shifters. (I have this bike if you want a reference, the only thing I've changed is the wheels.)
I made a few tiny fit adjustments on my ride tonight, I've got some other minor fit issues, like occasional numb bits and feet. I think my seat needs to be scootched forward and nose down just a teeny amount.

Anyway.
I'll keep working on it though to see if it helps.
I just did a side-by-side comparison (again) of the 105 shifters on the Mr.'s bike v. mine, and the throw is definitely less on the 105. (my handlebars are also definitely much more compact)