Hmm, I can't access that link either.
Changing the font in version 12 isn't that hard.
Go into your localisation file and you will notice the following lines:
Code:
-- nUI_L["font1"] = "Interface\\AddOns\\nUI\\Layouts\\Default\\Fonts\\ABF.ttf";
-- nUI_L["font1"] = "Interface\\AddOns\\nUI\\Layouts\\Default\\Fonts\\Accidental Presidency.ttf";
-- nUI_L["font1"] = "Interface\\AddOns\\nUI\\Layouts\\Default\\Fonts\\Adventure.ttf";
-- nUI_L["font1"] = "Interface\\AddOns\\nUI\\Layouts\\Default\\Fonts\\Bazooka.ttf";
nUI_L["font1"] = "Interface\\AddOns\\nUI\\Layouts\\Default\\Fonts\\Emblem.ttf";
-- nUI_L["font1"] = "Interface\\AddOns\\nUI\\Layouts\\Default\\Fonts\\Enigma__2.ttf";
-- nUI_L["font1"] = "Interface\\AddOns\\nUI\\Layouts\\Default\\Fonts\\Tw_Cen_MT_Bold.ttf";
-- nUI_L["font1"] = "Interface\\AddOns\\nUI\\Layouts\\Default\\Fonts\\VeraSe.ttf";
font1 is used for the chat log and I probably used the same with guildchat so changing that to a different font may help you.
The -- at the start of the lines denote a comment which mean it will ignore the line when looking at which font to use. So remove the -- on the line of the font you want to try and add -- at the start of the line that currently doesn't have any.
Then its the case of /rl or /console reloadui to get the new changes in play.