The transparent paints are not working out. It's very hard to tell when they've finally dried, and when I applied another layer on top of dry-to-the-touch paint today, it got streaky and lifted what was underneath. I had to wipe it off, and it left serious patches.
So I'm giving up on my idea of shimmering layers of translucent color.
I think the underpainting will be salvageable; I'll just use more opaque paint, like I normally do. If I had to scrap the grisaille at this point you would hear me screaming.