A little advice regarding WAV files: Try compressing your sound effects with
ADPCM, it's supported since RPG2000 1.50 and RPG2003 1.05 (or in other words: many years ago). That should save a lot of space even on highest quality option (ADPCM is a lossy type of compression, so don't set it too low). Also it's perfectly okay to use mono sounds (I'm not talking about music) instead of stereo, most notably if they are voiceclips.
Example: 「花嫁の冠」 / 「Hanayome no Kanmuri」 the first RPG2000 SampleGame has around 1700 compressed WAV voice files (at least the version found in RPG2000VALUE! and V!+) with 177kbps (uncompressed files tend to have ~1411kbps when using default settings in most programs) in the sounds folder. For a game that needs less than 140MB, the resulting audio quality is fantastic.
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