The experiment does explain how to bump up the gain from the basic 20:1 to 200:1, but I'm going to stay with the default setting for now. If anyone attempts the upgrade and has a video, let me know and I'll be happy to share here with an update.
For my circuit, I did have to make just three modifications. Obtaining two matching 68k resistors was easy (for the middle voltage), but I didn't have a .68 microfarad... in goes a 105 or 1microfarad. I had to substitute a .1 for the .047 microfarad, and I took Charles' advice to add a very large capacitor between + and GND... a 1000microfarad... that helped cut the noise substantially!
I did have the 10microfarad capacitors (x2) and the 330microfarad. After adding in the electret and the 50ohm speaker, you can see my final circuit below.
Initial tests were horrible... lots of static and hissing. Only after replacing the wires to the speaker with a 3' length of braided wire did I get some great results as you'll see in the video. The troubleshooting section is valuable... if you're having static and popping, there's probably a fix.