All of the mopheads I've seen have been in at least partial shade. I've never tried them, myself, but have the Annabelles and Limelights in both full sun and full shade.
Glowing Embers is gorgeous :)

Sunny mornings with afternoon shade is ideal for mop heads. They can even do well in full sun IF they have sufficient soil moisture. Like the vast majority of woody plants, they love a moist but well-drained soil. The problem, of course, is that well-drained soils are often not moist and normally moist soils are typically not well-drained. If conditions are like what I picture from your description, your soil is decent, and the area doesn't get extremely dry in the hottest months of summer, they should do great.

I have multiple mop head cultivar in the opposite light exposure conditions (early morning shade followed by baking hot full sun for the rest of the day). You can tell that mine aren't thrilled in the hottest summer months, but they do pretty well anyway. I do have to occasionally water them a few times per year during especially dry years.