Hi Tom,
I can say for sure that without a silver coat yellow paint is too transparent. Yellow paint has very little pigment. I tried to spray yellow over the Yellow Solartex and it didn't help much.
The issues I had with the Solartex having to be re-shrunk could be due to how I originally shrunk the fabric. Not sure? I am constantly having to re-shrink any plane I cover with monokote as well. The only time I have had to re-shrink a fabric covered plane is to remove a little dent from hangar rash.
Merry Christmas!!
Anthony