Top of the vertical works well on the -A models. On my -6 it's mounted on the fuselage bottom just forward of the tailwheel spring/rod. Don't have to worry about poking anyone in the eye that way
I installed a Comant CI-215 mounted on top of the vertical stabilizer with the elements pointing aft. It has given 7 years of good service first with a Terra NAV and then with the appropriate special in coax routing hardware both the Terra and a Garmin/Apollo SL-30. The elements are pointed aft for minimum drag and the elements quickly screw out for even less drag when racing. Most of the center element is covered by the vertical stabilizer cap. I did fabricate a simple aluminum base mount for service and position reasons.