@AhabGreybeard, wow, these look cool!
For lazy people there is also the possibility to use the ready-made preset “Rakurri Colourbrush Rainbowbrush”, from the bundle presented by @Rakurri here which can be downloaded for example from here, but then you deprive yourself of the fun and joy of experimenting!
Also, not everyone will like the “sparks” in the stroke of this preset…
Michelist