I think it's cool, probably overkill. Easy method I use, very similar.
Take a piece of metal spool wire, think electric fence. Cut off 14 feet. Fold in half. Tie one end to anything solid. Take a cordless drill, insert other end and stand 7 feet away. Turn on drill slowly and let it wrap together. Fairly tight. Remove from drill, remove from object, cut both ends.
Take it and insert it into the sunroof drain from the top, rotate slowly with a drill while squirting in some simple green, or similar. Go up and down a few times.
Go to the drains underneath with a metal wire tie, insert into slot of drain and stand clear.