Actually I think paint is a dominant over solid so:
Paint x Paint (if neither is homozygous): 1/4 will be homozygous, 1/2 will be heterozygous, and 1/4 will be solid.
Paint x Solid (paint isn't homozygous): 1/2 will be heterozygous and 1/2 will be solid.
Solid x Solid: will always produce a solid.
Homozygous Paint x Heterozygous Paint: 1/2 homozygous and 1/2 heterozygous.
Homozygous Paint x Homozygous Paint: 100% homozygous paints
Homozygous Paint x solid: 100% heterozygous paints
^^A little bit of overkill on that one.
And imo, there is no "point" of solid paints, but they are classified as paints because of their breeding.