Create your own or use already existing XML font template where all fonts are of the same desired size, then do the following:
Lua Code:
for i = 1, NUM_CHAT_WINDOWS do
_G["ChatFrame"..i]:SetFontObject("FontTemplateName")
_G["ChatFrame"..i]:MakeFontObjectCustom()
end
Using XML templates is important because atm only they support alphabets.
Blizz use SetFont to update chat frame's font size, but it updates only 1(?) out of 5 alphabets.
I asked Dan in IRC to add
SetRomanFont,
SetKoreanFont, etc methods to font strings and objects (created via
CreateFont) in addition to or in place of
SetFont because it's quite needed in EU and OC regions, he liked the suggestion, but it won't be implemented soon because it's a low priority task for them and because entire fontstring-related system is kinda messed up and it's not that easy to work on >_>