Well Sax, you must also realize that climb rate isn't really wing-loading related and the Spit VIII vs XVI isn't as complicated as you might think.
Honestly, if our Spit IX had a Merlin 66 engine it would perform identically to the Spit VIII, give or take 2-4 mph due to the VIII's retracted tailwheel.
Also, the Spit XVI actually is a Spitfire IX but with a Merlin 66 built in Detroit. That actually is the only difference. Believe it or not, it's not complicated at all. The Spitfire XVI's clipped wings add to its extra speed and the more aerodynamic wing gives it a better climb rate. In summation, a Spit XVI is indeed just like the VIII but with clipped wings (and a non-retracting tailwheel).
What inproves climb rate is the fact that the plane is more aerodynamic. That indeed helps climb rate and is one of the reasons why the P-51 climbs so well despite having a huge wing loading and low power-loading.
I'm actually 100% convinced a clipped wing Corsair will climb better, albeit not by much. But, hey, when you clip 8.5" of each wing resulting in the loss of 4.5 sq. ft. of wing area per wing, I think that's enough to do something. Plus, I have a soft spot for everything British.