For all of this topper talk, I went back and made my custom topper interactive!
First, use some T-Taps to cleanly splice into the existing flashers.
If you have never used them, they are pretty simple. Crimp down the folding part onto your existing wire and crimp down the spade connector to your new wire then attach the two by sliding the spade in. No soldering required!
Run all of the wires up through the back box - yeah I know I could have saved a bunch of wires by using one 5v source but I was feeling lazy.
Made a quick connect harness for when I eventually move the machine (the topper comes off easily with two screws too).
Put some color-coded flashers under each character.
Some flasher colors (like orange and purple) were not available so I used some color filters (amazon.com link »)
The finished product!
More videos that I am too lazy to upload to YouTube:
I especially like what happens when you start multi-ball