OK, better Google search terms led me to all the pictures I need of the non-turreted version, including a manual on the gunner's compartment. Building an A-20 Havoc Pacific Strafer pg2
Incidentally, I realized that the crash of the DB-7 on January 23, 1939, with Captain Maurice Chemidlin of the French Air Force aboard, which set off a firestorm among isolationists, happened in our neighborhood! The Douglas bomber crashed in the parking lot of the North American Aviation plant, injuring 10 on the ground.
And just to be weirder, the location of that plant is now the location of the LA Lakers' practice facility.
Great site; I've had it bookmarked for a while but haven't looked around. Google seems to be getting worse over the last few years. The first page might be close to what you are looking for and then goes off in a variety of tangents. Google images is now next to useless
Douglas XA-20F No. 69 "Porcupine I." Note the modified nose with the 37mm cannon barrel protruding about three feet and the two remote turrets, each with twin .50 cal. machine guns, in the dorsal and ventral positions. (U.S. Air Force photo)