I assembled the photo above from three images taken last night. First I used the Fuji X-T1 and 18-135mm lens to record the patriotic colors of the Empire State Building at dusk while there was still some blue color in the sky. Afterwards, I switched to the Fuji 55-200mm zoom to record the fireworks. My intent all along was to combine the fireworks photos to create other images so I zoomed in and out to capture them at varying sizes.
The exposure for the fireworks was f/16 at 5 seconds. Later in the evening, as the smoke built up and brightened the display, I decreased the exposure to f/22. The ISO was 200 and the camera set to manual focus at infinity. This is exactly the prescription I proposed in my post of yesterday.
Using Photoshop, I added the two fireworks as layers to make a red, white, and blue composition.. Because the backgrounds were completely black, I simply changed their layer mode to "screen" to blend them into the Empire State Building photo, and then tweaked things a bit to blend them in. I placed a mask over the Empire State Building to put the larger set of fireworks behind it.