ESIV: Oblivion experimenting

This is one for those truly experienced with the core game files, I've been mucking around with them a fair bit lately and as expected I've crashed the game more times than I'm proud to mention, but I'm trying to do something rather specific: change the in-game text font sizes in my inventory screen.

I've had a look at all the menu-related .xmls and found their font coding, but I can't seem to actually change anything in-game no matter how I alter them. I've tried removing all but one font from the oblivion_default.ini, I've tried - as I said - the .xml files too, but nothing's worked so far.

Anyone know how this can be done?