I designed and 3D printed a set of insert holder turrets compatible with the “High Precision Watch Hands Fitting Tool – 10 Sizes” from AliExpress.

They fit perfectly and make the tool much more practical to use.
You can also add a spring (size 7x25mm) to better replicate the feel and behavior of more expensive professional tools.

Links:
Tool: https://it.aliexpress.com/item/1005008958734294.html?spm=a2g0o.order_list.order_list_main.167.1ab01802AUA9Ex&gatewayAdapt=glo2ita
Springs: https://it.aliexpress.com/item/1005003784805422.html?spm=a2g0o.order_list.order_list_main.182.1ab01802AUA9Ex&gatewayAdapt=glo2ita

Print notes:
Printed on a Bambu Lab P1S using Bambu Lab Matte Ivory White filament, with default settings (the slicer automatically adds the brim).
Everything fits spot on, and the inserts even make a nice “click” when seated in place.