Neon with paint shaper

In going through my photos, looking for samples with this tool, I came across these (I totally forgot about!!) They're from one of my first 100 Day challenges (100 Days of Neon, early 2021).

i tried painting a layer of neon orange over black, but it didn't show up well.

Diff. lighting

Here's my first try: (Ugh, my lettering -- yuck.) I first painted a base with neon colors (another piece from my 100 Days of Neon) then an overlay in grey. It didn't turn out b/c the grey dried quickly.

*SO, 1) Use good paint, 2) make sure the layer is thick enough, and 3) work quickly!