Late to the party but think we should clear up a few things.
First is that the 4 cannon Spit Vc was not common. The only actual combat use I can find is 2 SAAF in the ground attack role in 44-45. These were not clipped wing aircraft and had the Vokes filter under the nose. They also carried a 500 pounder on the centerline. They were NOT dogfighters and with the Vokes filter and extra weight would have been at a real disadvantage.
There are lots of photos of 4 cannon Spit Vc launching off Wasp to reinforce Malta. They had two of the cannon removed when they got there to save weight and help performance.
Clipped wings on the Spit started with the experimental Spit III that had the first internal armored glass windscreen and retractable tail wheel.
The Spit V in all it's forms, Va, Vb and Vc was capable of having the wings clipped and many were when they started using the derated Merlin 45s and came up with the LFv. Clipping the wings was often done in the field and basically involved removing curved tip and fitting a piece of wood on the end and sanding it to fit.
The Spit XII had clipped wings in production and follow on Spit VIII, IX, XVI XIV etc all were flown with clipped wings.
The Spit V should be able to carry a 30, 45 or 90 gallon slipper tank as that was regular practice in squadron service.
All that being said, I wouldn't advocate for a 4 cannon Spit. A Spit LFIXe or XVIe would be a much better addition.
image is of 4 cannon 2 Squadron SAAF Spits over the Adriatic in 44-45
Dan/Slack
