I like the 3-combination padlock kit card, but I only wanted it to lock my gate so my child can't get out. A 3-digit combination padlock takes too much time to unlock if I have to use it daily. So I modified just the dial so that it is no longer 3-digit combination, just turning the longest hand to the center to unlock. That's sufficient to prevent my child from unlocking, but still easy for me without remembering any combination.

You will have to print the original here https://makerworld.com/en/models/95082?from=search#profileId-107490, then replace the dial with the one I added.

There are 2 plates, one labelled 100%, another 150%. 

That's because the stl file shared by the original source is at 100%, but his 3mf file is that of 150%. So if you are printing his without modification, then you should print the 150% model.