Ok, here’s what the measurement came out to....90”!
According to the NOAA charts, after subtracting three inches to account for the difference between fork and tail length, your fish probably weighed in around 275lbs
I've been informed the weights in the NOAA chart are probably a little on the light side, seeing as they were generated from fish caught by long liners that probably lost some weight before being measured and weighed. If Joe's fish was a healthy piggy female, it was easily 300lbs!
For comparison purposes, a fish measured tip to tail that is one foot longer projects to 400 pounds!
Unless the fish beaches itself for you, I believe 8' tip to tail is realistically approaching the upper limit of what can be caught by surf casting gear for these beasts. Anything bigger and you're going to need a real shark stick and reel to land it. If you're using a shark stick, I highly recommend a full fighting harness you can clip into. If you don't have a harness, then I'd suggest that you take a page from the Florida guys and get a 12" piece of aluminum tubing that will fit over the butt of your shark stick so you can stick it in the ground and use that as your "fighting chair."
I think you're looking into this too much. You don't need a beach butt unless you're running 130+ line or rely on them solely as the way to anchor your rod instead of using a sand spike. Also, extending it with pipe isn't a good idea. If you have blank through construction there's a good chance it'll break inside the pipe below the reel seat. Especially if you don't strip the butt and fit It correctly. Also, aluminum pipe and thin stainless has been know to bend. Make sure it's thick enough or go galvanized.
We got all the recommendations from Chip (backbayman) on what to do, but I want to hear from our most experienced shark angler on here. Give me a solid run down Chris on what to expect and what to do from beginning to end!!
Inspect your gear, don't cut corners, expect the worst and pray for the best.
Honestly it's not that difficult. If you don't have much experience bring someone with the same or more experience than you. Make a good tail rope, D rings are your friend. After the initial hookup your going to want to put everything you can into the bigger fish, we have so much structure and kelp to get cut on and tangled in you have to turn them or atleast keep them close to shore. It's easy with whites, they just do circles, from 6ft to 15.2ft, they do circles so be prepared to reel like hell and put all your weight into your rod in a matter of seconds. Once you can leader them they go where their nose is pointed, they aren't blocky and soft, you point their nose toward shore and their body follows, time it right with the waves and they'll swim right on the sand. Don't try to hand them without the tail rope, they're strong and will beat you or themselves up. Put the rope on and face them into the waves, unhook or cut the leader and then use the rope to turn them and pull them into deeper water. Again they're strong and the only fish I've ever had actually lung at me trying to bite so use the rope as stand off. Once in deep enough water you can easily control them by the tail and unclip the rope and point them on their way. And remember to keep them in the water the whole time and move with a purpose. You never know if it's a white, mako, thresher, hammer or 7 gill until it's in the skinny water but when you ID it as a white your whole mission in life is to get it swimming again. Keep a camera rolling and take still shots later.