Tip: Switch palace switches normally disappear if you replay the level. However, if you insert them as direct Map16 and use the hex-edit at $00EEB2 in the ROM map, you can replay the level without a problem.
A few quick notes. I swapped #optimized to #default since it inserted fine, make sure to always check that. Also, you could loop some of those big bunches of single notes on channel #4 to save a handful of bytes, and also maybe lower the global volume a bit.