ok...the base is 1/2 brick, 1/2 streamlined. Cd 0.28
your rear end treatment is complex...so it's no longer a simple a + b.
i didn't say that the wing was out of the airflow. i said it wouldn't generate downforce. wings need to be at least 2 chord lengths (iirc) away from the body to work. imagine the low pressure below the wing, is the same low pressure above the body...they cancel each other out. imo at best it will add drag.
1970's thinking was that spoilers, dams and fences would "fix" aero problems. they're bandaid fixes. a radius on all the vertical surfaces that's >10% of the thickness (of the base) will do more for you than fences. can you put a fillet where the greenhouse meets the base? taper the nose and tail a little? i like the P4/5 nose/tail treatment.
thanks for the pic. i was actually thinking of raking the body a few degrees (like a wedge) to reduce lift. taper the rear of the body 13* (my research indicates this is optimal in your situation). it's all in the details.