Good job with the scaling. I did my own. Assuming the booklet is...

Good job with the scaling.

I did my own. Assuming the booklet is an A4 sizing (very likely, as binder is 21 rings), we can easily find a scale. Size of A4 is 297mm x 210mm.

There are 21 rings in the binder, 20 spaces between the rings, plus half spaces for either ends. So 297mm / (21+20+0.5+0.5) = 7.07mm each 'spacing'.

Extrapolate from ring to other side of book gives the bottom of the M in the logo, to the side apex of the gem is 6 spacings, gives us 42.4mm. We can now tell each of those is about 10-20mm depending on orientation.