You've examined the image attached more than a few times. The drummer "boy" and company color bearer just above the trunnion of gun no. 1 are easy to spot. However, I've never paid particular attention to the AVC uniform of the gun crew commander in the foreground. He's standing in front of the wheel hub of the gun. Since the "Tallapoosa Rifles" organized as an AVC company, all officers and men probably had such uniforms.

Since it's May and a bit warm near the beach at Pensacola, most enlisted men are in shirt sleeves.

There are nine guns on barbette carriages in this image, six men per gun crew. Counting the two officers standing on the parapet, plus the drummer and ensign and a couple of others, there appear to be about sixty men in this image.