I tried the method in the first video but the holes in the bike frame are too small. The cable ferrule won't fit. It's 6 mm diameter. I looked online for cable routing kits but all say the hole has to be 6 mm or larger.
I tried the thread method in the second video and it wouldn't fish to the bottom hole. The thread would just bunch up in the middle somewhere.
I made cables with a small magnets on the end (super glue) and fed one through one hole and the other cable through the other hole, hoping they would meet in the middle, connect and I could pull them out one of the holes. Didn't work.
I tried to feed one of the cables with a magnet on it while using a very strong rare earth magnet on the outside to guide it through. It didn't work.
I ordered a cable routing kit and I plan to drill out the holes as needed. First problem was my drill would not fit on the top hole due to the seat QR weldments. So, I ordered a DEWALT Right Angle Attachment, Flex Shaft and a set of impact drills. All orders come in tomorrow. Done for the day.