Here’s a short video that shows the process of retrieving the film leader. It’s not superbly methodical; essentially you need to twist the spool whenever the retriever tool feels too tight when you try to push the next plastic tongue in. Other than that, with some practice, it gets easier: youtube.com/shorts/3ADmdia…
Plus, it’s faster to load film into a Patterson spool and you get to keep a canister that you can use for bulk loading later. Or, once you accumulate a bunch of used canisters you can sell them to someone looking to bulk load.
YouTube Video