This looks really good and I appreciate the length and detail of the description, thank you for this.
I'd like to see a variant for Euro coins, sizes can be found here for example: https://www.mdm.de/muenzwelt/euro-muenzen-uebersicht/gewicht-euromuenzen (5 cent or higher as there are countries not having the 1+2 cent coins).
Might be just me, but ribbing I found to be hit or miss depending on fingers and sizes, knurling however works well and I'd like to see an option for this.
Thanks for making these!