Important: must be placed in Data folder, NOT Override folder.

DIY File Modification
Open the file \Data\2da00.bif with a hex-editor (ex: XVI32) and change the following lines:

Label TrueType PointsOutlineMinSize
default arial 16 1 11 
console lucon 14 1 10 
smallinfo arial 16 1 11 
gui_infopanel garamond 30 1 11 
gui_default garamonds18 0 11 
gui_label garamonds24 1 11 
gui_bigger garamonds24 1 11 
gui_huge garamond 30 1 11 
gui_icon garamonds18 0 11 
gui_infopanel_biggaramond 30 1 10 
fnt_galahad14 arial 16 1 11 
subtitle arial 20 1 11 
choices arial 16 1 11 
tutorial garamond 20 0 11 
credits garamond 30 1 11

to this (reference fonts and sizes from \System\__cache):

Label TrueType PointsOutlineMinSize
default arial 23 1 23 
console lucon 16 1 16 
smallinfo arial 23 1 23 
gui_infopanel garamond 35 1 35 
gui_default garamonds28 1 28 
gui_label garamonds28 1 28 
gui_bigger garamonds28 1 28 
gui_huge garamond 35 1 35 
gui_icon garamonds28 1 28 
gui_infopanel_biggaramond 35 1 35 
fnt_galahad14 arial 23 1 23 
subtitle arial 23 1 23 
choices arial 23 1 23 
tutorial garamond 23 0 23 
credits garamond 35 1 35

Used the biggest sizes available for each font and changed the gui_default and gui_icon normal font (garamonds_n.fontcache) to the outlined font (garamonds_o.fontcache).

Uploaded with permission from Antr4cite