In reality, the latter marks of the Gustav were a real pig of an aeroplane. Too heavy, they had to be flown at near full power in the landing circuit, or they would fall out of the air.
The early "F" was the real Pilot's aeroplane. Light on armament, it was a great dogfighter. When the F-4 and later marks with gondola wing mounted cannon came in, they went downhill.
LJB