Welcome along!
What a way to start the hobby(again).
I'm still working on assembling my first Stegadon.
Like the colorscheme, I would recommend the same about the washes, especially on the lighter basecolors(horns in your case)
If you want to paint some areas in gradient colors(by applying washes) you can best end your brushstrokes at the point where it needs to be darker. As the wash tent to collect at those points.
Keep up the good work
I'd like to see the model once complete
Gr, Imrahil