Hello 357: Yeah the 80 inch long element length sounds right, for the CB Band. The Instructions say to mark the 48 inch long fiber glass rods at 43 11/16 or 43.6875 inches, and install them into the 5/8 tubing, this added with the 36 inch long 5/8 aluminum tubing comes to 79 11/16 or 79.6875 inches measured from the fiberglass tip center of the hole to the end of the aluminum tubing. So end to end 80 inches sounds pretty close.
See the link I left you in the first reply, its the assembly instructions with all the lengths and such.
They used 14 gauge cheap wire for the quad elements, again ok for saving money in a mass produced product, but not for "Bitchen" antennas guys. I use 10 gauge wire the good stuff so that is will better resist stretching over the years. Amidon has it, its called
Thermaleze-Coated Magnet Wire its bullet proof and has a very tough insulation that will need to be scrapped off and solder tinned.
Your metal Hubs being a solid piece of aluminum are just fine, the insulated Hub looks like it was possible made by Avanti in early models, or someone had them made.
Rebuilding the old Moonraker 4 and 6 element beam antennas, I used custom made Hubs that had a 2 inch hole allowing a 2 inch Mast to be used, adding strength for a much longer beam antenna. Those with the original equipment of the cast aluminum Hubs need to be very careful when tightening down the bolt that holds them onto the mast. As time will allow for corrosion and cracks. Using a solid piece of aluminum for the Hub will work very well as you have, the 5/8 inch element could have a 1/2 inch solid piece of aluminum rod installed to allow them to have the bolts go thru them without the bolts flatting them when tightened.
Jay in the Great Mojave Desert