Weezie
I called a friend at the hardware store and asked your question, I know your not leaning to krylon spray but that is the best for plastic.
However I asked if you did a primer like i mentioned he said about the same thing i did,re-touching would be.
but he also said since you wanted to paint with a brush you could get a can of krylon and cover your project and then when dry paint by hand what you want, since it will be covered and adhered then.
What are working on, the creative wheels are spinning
you have me curious...
Hope that helps a bit
Angie