Use the ExHiROM section. Unlike me, you don't need to have backward compatibility.
Your hack only uses about 100 KB of the ExHiROM section. Plenty of space in there.
I was almost going to, but I think I just found my place. Turns out the area I used for the beta naming fix has enough space and is completely unused, so all aboard 0x41F400.
About backwards compat: I like the idea of keeping things as welcoming as possible for new translations (yep, one's been done before) so I try to be as simple for everyone to get things working as possible. At the same time minus the element signs, credits, and the time menu it's all straight text. Not very many graphics to edit that I can think of. So it probably would've been fine.
EDIT: And there we go! One change between mine and the tutorial: I did not need to add 0xC0 because the space is past 0x400000. Only thing left is getting Antiquity right, edit the mentions in text, and we're done. I may put up a quick IPS for only the graphics, if anyone wants it.