Davinia, SO delighted you found my lessons helpful, and such as wonderful inspirational image as a result! Who could want a better testimonial.
Superimpose is ABSOLUTELY my go-to layering app - once you discover it's strengths, it only gets better. I know the developer quite well, and I'm on the beta team for this app and Leonardo, his other great app. But quite frankly, I really haven't mastered Leonardo's selection tools, and it also does not save in as high a image resolution as Superimpose does (3096 pixels vs. 3500 wide).
As you go through the lessons, be sure to do the ones labeled Android as well. I used Photoshop Touch in some of those, and that's another great layering program when you want to see several layers active (up to four over the base) at once and adjust different ones to see the cumulative effect.
Congratulations on a fine piece of work, and thank you again for the very kind words!
Best,
Bob