Unrelated, but gotta ask: ckrit, wanna play go sometime?
*edit1; As I vaguely recall reading a long time ago, GBA games use S-JIS encoding, and in good form Hikaru no Go 1 and 2 both use S-JIS encoding, and neither script is compressed.
*edit2; These are sort of raw and incomplete, but they were super easy to make with EsperKnight's SJIS dumper
hikaru no go 1 script dump
hikaru no go 2 script dump
I think the easiest workflow is to make a proper table file full of control codes, dump with cartographer, and insert with Atlas. Therefore, I wouldn't necessarily try to start translating with these rough scripts, but you can get an idea of the size and scope, I guess.