1.23 supports most of 0-255, though 16-62ish run the risk of interfering with animated tiles. However, using the strings from 63ish on is a risky endeavor that we know very little about -- it overwrites some memory that JJ2 wants to use for other purposes, but we don't know what direct effect this has. TSF, on the other hand, seems to refuse to load any text string higher than 15.