My 10' mast is mounted to a 33' old tv tower. The mast itself is made from a 10'; 1-3/8" chain link fence top rail. I also purchased 2 packs(4 total) of these panel clamps to attach the mast to my 1-1/4" tower leg. I then cut off the end of the top rail that will accept another rail. This piece will be the base and allow you to turn the mast to aim antennas. Once you mount the base tightly using a panel clamp you can slip the mast on it and pop another panel clamp on the mast to the tower to hold it in place. While brainstorming this setup in Menards i figured if this didn't work, another idea would be these gate hinges bolted together but the panel clamps worked perfectly for my specific setup. I then mounted my antenna brackets to the mast using a flat surface so they would both be in sync with each other(pointing the same direction). Attached antennas to the mounts and installed 90° n connectors. Hooked up my 50' lmr400 cables to each antenna. Make sure they're very tight but don't strip them. Wiped them down with alcohol to remove any oil from my hands and wrapped with scotch butyl rubber tape. Then squeezed the tape together to make a nice waterproof seal. Then wrap electrical tape over the butyl tape so the butyl tape is UV protected. When wrapping you want to start from the bottom up overlapping to create a shingling of tape so the water can run off. There's good YouTube videos out there about weatherproofing coax. I climbed my tower and mounted the base about 3' below the top to give my panel clamps plenty of bite on the mast. Now the hardest part is to climb the tower with the 10' mast, antennas mounted, and cables dangling off. I'd suggest getting help doing this unless you are pretty physically fit. The way i did it by myself was climbing each rung and reaching through the center of the tower rungs and grabbed the mast. That helped me keep balance and ensured i couldn't fall while reaching for the next rung.
Now for the lightning protection. I started by bonding each of my tower legs with a 5' piece of #4 bare copper wire to an 8' copper grounding rod. Before running the copper wire around the legs I wire wheeled off the galvanized coating down to bare steel. Then bonded/clamped them to each leg using stainless steel hose clamps. Finished the base ground by burying the exposed ground rod.
This next part is *not* recommended per the lightning arrester manufacturers but I did it anyway. The lightning arresters are supposed to be outside before entering a building and grounded with #8 bare copper wire. I mounted mine inside because I wanted the least amount of coax connectors exposed to the elements as possible and the least amount of connectors as possible to minimize signal loss. So I repeat *do this at your own risk!*
I was aiming for a clean looking install inside of the house even though nobody will ever see it in my closet. (I'm ocd

I purchased these blank "build a faceplate" pieces at Menards. Drilled out 5/8" holes on 3 of the faceplates. This custom stuff on plastic parts takes some time and patience.