I agree those tools are brilliant I need to make some myself sometime along with his other tools ( I keep forgetting to write down the information I see 🥺or find someone who speaks Japanese to translate the steps into English)
Those Len's are worth having in your parts collection ( I have the yellow Len's ) you never know when you might need them 🤔 and sometimes easier to use than scratch building ( a skill worth learning just in case you need it for unique parts 😉)