Mike,
I not sure what you are looking for. I have three openings in the cabin sole: one forward of the compression post and two aft of the post. That's all I know of. You can see all the way to the bottom of the bilge from the third opening.

I've seen several locations for batteries in various Commanders. The terminal strip is usually (not always) on the starboard side mounted on the interior of cockpit wall. I originally found my battery in the starboard cockpit locker just aft of the terminal strip. I've seen them under the cockpit floor behind the wall between the cabin and the stern. To me both those locations made the batteries hard to move and service. I relocated mine to a battery box in the cabin under the bridge deck just aft of the ladder. I have it strapped to the wall. It puts it low and centered in the boat and is easy to get too when needed.

Does this help?