Add optional argument for font-size

[orangenschalen]

The default font sizes are a bit small (to add a more "objective" criterion: it causes more than 90 characters per line) especially with my preferred font: "Latin Modern Roman 12". If the font-size could be made configurable like the font, that would be great.

[Sematre]

The default size of the letter body is not changed by this template. It only has fixed font sizes for content that is not part of the body.

Here's an overview of the different font sizes thought this template (layout overview):

• Header (10pt)
• Sender box (7pt)
• Annotations box (7pt)
• Recipient box (10pt)
• Reference signs (key: 8pt, value: 10pt)
• Information box (unchanged)
• Date (unchanged)
• Subject (unchanged)
• Body (unchanged)
• Footer (unchanged)

So am I correct to assume, that the issue is with one (or more) of these sizes and not the body?

The font size of the body parts can be changed as usual like this:

#import "@preview/letter-pro:3.0.0": letter-simple

#set text(16pt)

#show: letter-simple.with(
  // ...
)

[orangenschalen]

You're mostly correct. All the glyphs are somewhat tiny with the aforementioned font. I used the scaling via

#set text(13pt)

but the rather small address is not nice for the postal workers and the layout starts to looks uneven.
If I create a patch, where all the different fontsizes are calculated as an offset from a global fontsize, such that with the default value for the global fontsize nothing would change, but a global scale up would be possible, would you be interested to merge that?