This is just an off-the-wall suggestion, but I don't think a 1941 spitV really fits well in a 1943 scenario. What about substituting the SeaFire for the SpitV? It's a little heavier (but not terribly so), has similar performance, but twice the ammo load (as the later SpitVs had).
Primarily I'm thinking of the ammo load. Seafire's the closest thing to a spitVc.
Any chance of that happening?