It's been said before; these are amazing times. With the global flea-market and antique-shop that is the internet, it was possible to find and purchase for a very reasonable sum the correct pattern screwdriver for the re-boxed nickel-set.
To be fair, for a mid-twenties set it would more likely be the longer, closed nickel item. This type is more common in 1915 sets than '25 sets. But this is the exact pattern as shown in the parts-list in the 1920 booklet.
It is again confirmed. There is not a niche-interest so tiny that it is not served somewhere on the internet.