First Train Horn Install

Hi all newbie to the group and train horns,

I’m going to be installing the HornBlasters dual tank 6 Horn tire delete kit on my truck. And was wondering if I should run a 6 or 4 awg power and ground wires to distribution blocks near the back of the truck to so I can then install relays to all power wires. Also if I run the 4 or 6 not sure what size fuse to use. Any advice or is this over kill?