That adapter should work fine. However, of us with CBs just wire them in to the truck. I wired mine into the circuit for the lower 12v outlet which is always on, so I can use the CB with the ignition off. It took maybe 10 minutes to wire it in, and I didn't have to give up an outlet.
^^^Exactly. If you wire it to the lower 12V outlet in the lower dash you don't even have to drill holes, just run the wire around between the center dash and the glove box. If you mount the CB in the little tray that is down there the bulk of the radio hides the wires, and it makes the mic easy to grab since it's down by the shifter.
I like the location so much I put the faceplate for my VHF/UHF ham radio down there too