I'd still verify the actual gearing that is in each chaincase. Based on your info above, if your reverse setup is 38/22 (1.73), and his Vmax setup is 41/20 (2.05), the sled will perform differently, as Devilin alluded to.
That said, I wouldn't think that 41/20 gearing would have come stock in a Vmax700. I would expect something closer to the 1.73 - 1.80 ish ratio. Maybe it has been changed out in the past, for quicker acceleration.
It also seems odd that a the 99 700's would have such a wide range of ratios from non-reverse 41/20 (2.05), to reverse 39/23 (1.70). Is the 2.05 for a mountain sled?
All of this tells me to verify the specs based on the actual sled model, but even more importantly verify what is actually in each chaincase, else there is no way to tell what the difference in performance may be. With reverse gears, I don't think there are too many options for the lower gear tooth count since it is unique to the reverse setup. The top gear will offer more tooth count choices since it interchanges between reverse and non-reverse. Changing gears may necessitate a change chain length as well, and in any case keep all gears/chain in a set (all HYVO or all non-HYVO) as sideshow mentioned.
