1. The Mk V looks and flies like a VB, yet it has the VC's ammo capacity for the cannons? Remove the extra ammo and call it a VB.
2. The Mk V is missing it's 250lb wing bombs. Possibly the 30 and 90 gallon slipper tanks should be added too.
3. Add Mk VC(T) with 4x20mm, with the option to remove 2x20mm, as was done to Malta Spits. The VC(T) would perform much worse than the VB thanks to the added weight and drag from desert survival gear and Vokes filter etc.
4. Make the F.IX a "real" 1942 plane, not some hybrid of 1944 options with a 1942 engine. Remove the GERMAN 300l drop tank, add the 30/90 gallon slipper tanks, and remove the 1944 "E wing" and rockets.
5. Add a "real" 1944 Spitfire - LF.XVI, with the rear vision fuselage(teardrop canopy). Larger fin, "E wing" guns, rear fuselage fuel tanks, 50 gallon torpedo drop tank, same bombloads as Mk V and IX.
Concerning rockets; the RAF never used them in combat on Spitfires during WW2. They did test several types and installations though. However, other air forces equipped with the Spitfire did use rockets, the first time being in December 1944(Mk IX).