What’s the ideal width for a pair of scales in mm?

Very quick question: What’s the ideal width for a pair of scales in mm? I don't have time to search today, so I decided to ask the question!

I'm currently cutting some blanks; however, I think they are a little thick.

Thanks for the help folks.

1/8 inch slab which equals 3.175 mm.

After sanding, etc.. it ends up being somewhat less but in general that's a good the size to start with.

Yep +1 with the "Mad Max"
The only time I start slightly thicker is when I am working with a heavy wedge then I will start at 3/16 or about 4mm...