you know pervert, I have never even thought of what the effects of fuel sloshing around in the tank could have on a plane in game, I am interested to hear an answer to this aswell
I'm stabbing in the dark here tbh but I'd say if it was a big issue there would be some form of baffles to restrict how much fluid could move at the same time? I do know that in WW1 it was simply a tank though and wondered if the movement of a large amount of liquid as a whole would destabilise a plane like the camel
from wiki
"The Camel owed both its extreme manoeuvrability and its difficult handling characteristics to the placement of the engine, pilot, guns and fuel tank (some 90% of the weight of the craft) within the front seven feet of the aircraft"

As you can see it is pretty much a big tank or 2 tanks to be precise, the same would probably hold true for the oil tank, thats a lot of liquid moving around.
Another thing I thought the other night was that for a plane with so much weight in the nose the F1 really wants to do bugger all with it, a lot of slow nose over attempts amount to squat the d7 on the other hand will have the nose drop over quite readily on vertical moves.
Yet another quote from wiki
"The Camel soon gained an unfortunate reputation with student pilots. The Clerget engine was particularly sensitive to fuel mixture control, and incorrect settings often caused the engine to choke and cut out during take-off. Many crashed due to mishandling on take-off when a
full fuel tank affected the centre of gravity."