It's finished! I was expecting it to take me a month but it only took three days.
It's comprised of a printed cotton outer layer with two layers of fleece inside. Between the two fleece layers is a pocket that I can insert a cloth or disposable booster pad inside. I used a Tena slip as a template and it fits well but in retrospect I think I should have made the front tabs longer, and I will do that for the next one (I have enough fabric left to make at least one more).
Photos show nappy with 6-layer terry booster pad inside. It's very soft and comfortable to wear.