The good news is: with the exception of "Karn Evil 9" from ELP at the beginning, all the other demonstrated songs fit into memory! The ELP song is also problematic from a MIDI timing / MIDI data density point of view. I really like that Bach's Toccata & Fugue in D minor (BWV 565) barely fits completely - just a few bytes left! I didn't fully play it in the video. I also think that CANYON.MID (last song) comes across really nicely and authentic.
Running out of RAM with more complex songs... need to figure out how to use the 128 KBs of the Model 4 :-)