Spitfires and High Speed Roll Rate

[Anaxogoras]

Not sure what you're getting at, but look at the difference when wing tanks are full/empty for instance.

I'm getting at the fact that all of those aircraft underwent changes in weight and weight distribution without the effects we observe in the transition from the V to IX.

It's also possible that the V rolls too well.  Look at the old numbers from Warbirds.  Back then HT had the Spit V rolling much more slowly at 400mph.

[Angus]

The V should AFAIK roll slightly better than the IX, - it's all muscle powered and the aircraft is lighter.
The V had a very delicate C.o.G. by the way. While that had a very big effect on pitch, I am not sure on roll.
The IX would be more nose heavy.
With a flick-roll, the V would definately be swifter than the IX, however a Mk I would be even swifter while being unmoveable at speeds where the other ones could still roll...