The variation you are pointing out, to my awareness, is a function of the person doing the hot-stamping and these variations are not a function of the type being used, i.e., being a larger font. Instead, the variables of hot-stamping are at play here. Thos variables are as follows:

1. Heat. Not hot enough will leave a weak hot-stamp and thin lettering. Too hot can produce a bold, deep hot-stamp and thick lettering.

2. Pressure. Not enough will leave a weak hot-stamp and thin lettering. Too much can produce a bold, deep hot-stamp and thick lettering.

3. Duration of application. Not enough time will leave a weak hot-stamp and thin lettering. Too long can produce a bold, deep hot-stamp and thick lettering.

Then you can complicate this mess with having two or more of the above being out of adjustment!

Didn't know that there were that many variables to hot-stamping, eh?

Jim