I belive the Spitfire V (and getting more detailed, the Vb) was the most common of the Spitfires. Am I wrong?
Anyway, To make a proper full house of Spits, we need at least three, the VIII, the IXLF, and the 21, and maybe even more.
After all, the Spits of WW2 were more than 20.000, and were used into the Sixties if I remember right.
But again, for Aces High, an unperked access to the uber spits would really upset the game balance, - they are just so good aircraft. So, I say we'd have to perk them. The ENY and OBJ values will come into that too. I'd vote for a low perk with relatively low ENY value. Good to get kills in them, but not exactly the planes to sweep up perks.
IMHO the Spit XIV is way to expensive BTW.