Help with Radio and GPS Install

[qc71]

Hi, we are going to be installing Police Scanner and GPS System in 2004 chevy silverado crew cab z71 and will be using Bussmann BP/HHH ATM Add-A-Fuse on the Instrument Panel Fuse Block we would like to use always on circuit for the Police Scanner looking for one that is not used to much want to avoid any interference, on the GPS we might want BP/HHH ATM Add-A-Fuse to be on the car ignition circuit, but if you can tell about always on circuit also any help would be greatly appreciated