Sorry, I didn't forget about you man. I had to make my chow run.
The video shows yep, exactly how thats done. But they don't show pressure testing it after installation. Notice they use the nylon rod for that because theres not really a rod that matches that plastic close enough to become one with it. Plastic welding or epoxy either way will eventually fail one day, if it ever seals to begin with. These guys are telling you right about the prep. But if its below the water line when cool where yours is broken, of course the best repair would be with the radiator out and not leaking thru your repair as you try to fix it.