In general terms, faster is bigger.....as far as how the motor sees it.

At least, that's how I always looked at it.

So....... If you would have thought a "bigger" cam than the previous one would have been better with the motor in its current configuration ...... Then "faster" is a step in that direction.

If you wanted to see if the combo will respond to more (hi lift)area under the curve, without really going bigger....... Then a commensurate reduction in duration would accompany the added rate.

You probably haven't really made any representative pulls yet though, so the jury is still out on the new cam.
It might be safe to say though, that "big gains" aren't in the cards.