None of the Hydrangea macrophylla like Endless Summer will work in afternoon sun. It will wilt and get crispy-edged leaves since the roots can't replace the transpiration of the large leaves fast enough in intense afternoon sun, especially against a sun-heated western facing wall. In your zone, you might get away with one of the Hydrangea paniculata types if you give it adequate water. I can grow them in full sun (6 hours of afternoon sun qualifies as full sun, though mine are in 12+) but your hotter temperatures and more intense sun might not work, and mine aren't planted against a building. I'd ask on the Hydrangea forum since there are posters there in warmer climates and it is fairly active.