Using digits as goal binded progress bar

I tried to build some code to bind a progress bar to the numbers of the digital time like the minutes in the picture.

The problem I run into is that I cannot get the correct data for the height. I tried the function from Hr. Mortensen getApproxNumberFontHeightInPixels, but that is also not a reliable fix to this problem as I still run into problems with other device than my Venu3. Is there another reliable solution for this, or is best to build this using graphics?

What would your aprouch be?