Thanks for the rapid reply. I’ll have to try those settings.
I’m able to place a control point in these areas, and have at least 3, but usually 4 photos covering it.
It was extremely difficult to get good alignment, I believe due to the subtle marble pattern and relatively low overlap. (It’s about 75% overlap, but only 62% “sidelap” (thanks, python image library). The only other time I’ve seen this before was with black tarps over a facade, which acted like a mask and just didn’t mesh.