Is it possible to change font size for labels?

I tried font scale but that messes up with everything else.
A per label font size and a global dialog font size would be great.

For example in this dialog?

(dlgname,'Error', bok=0, bcancel=1, w=800, h=400, bw=150, bh=40)
(dlg, 'Spindel kann nicht bei eingesetzter Messonde eingeschaltet werden.', typ=label, x=20, w=600, color=0xfff0000)
(dlgshow)

And before I forget:
Is it possible to use svg images in dialogs?