While Im not sure how to impliment the Arado rear gun, Im dubious of its impact anyway. The Arado is a very rare bird in the MA now because it doesnt have any impact. Theres just not much use for a high speed bomber that carries half (or less) the payload of 3/4 of the attack FIGHTERS.
At its current price, its just not worth it. Ive never been shot down in an arado, and Ive flown 10 or so missions in it, but I really only use it on a lark, and not for any particular tactical/fun reason. The actual aircraft carried about 3000 lbs of bombs (roughly based on metric conversion). Now I know the AH version carries 3x500, but all bombers seem to have an adjusted payload, and this is what neuters the arado. 1500 lbs of boms isnt enough to destroy a hanger, and its limitation of 3 bombs means its not useful for de-acking ect.
Its a neat plane, just not a very MA type of ride. Now with the 262 in the MA, the arado is little more than a death trap.