Aside from the lower rate of fire, one would think that it would be easier to get a hit on an aerial target, since the balistics were better.
I can't imagine the weight is a whole lot greater than the 1800kg egg. Was the drag really that bad on the BK 37 gondolas?
Lets take this back to high school physics.
Put a bowling ball in your backpack and do a cartwheel.
Now try doing a cartwheel with a shotput in each hand.
Now anyone who goes out in a stuka looking for air to air kills is a fool.