am I on the right track? re: actuators

This is my first time using linear actuators. I am going to purchase one with about 3" of travel. Anyway, I am putting dual 4' CB and scanner antennas on the roof of my Cherokee and I wanted to create an antenna bar that would be motorized and controlled via a swith inside, so I can lay the antennas down flat against the roof when clearance is needed. Any comments or suggestions on this setup below? My main concern is whether to use 1 single linear actuator in the middle of the bar, or 1 at each end of the bar?

here's the pics:

I'd say just use one.My ex once told me I have a perfect face for radio.

keep in mind, the bar is 4 feet across, and slightly flexible, so I didn't know if one actuator on each end would stiffen it up a little and keep it from warping or flexing in the middle

Why not machine a bar out of aluminum to mount them?  I don't think I'd want an antenna mount to flex.My ex once told me I have a perfect face for radio.

It's made out of glavanized steel. Thing is I really don't want this to turn into a real expensive project. Looking at about $75 total right now. I think if I mount two of these pieces together and bolt them every foot then the flexing should be much less