I hate to follow up my own post, but after some further research, I noticed a slight miscalculation on my part. Looking at
this IFI FAQ, the victor speed controllers are obviously going full range at 1-2ms, more or less. The IFI RC is changing the PWM width in 5 us steps, so it's varying the pulse width by 1.275 ms, and we're not using .275 of that range. So the output on the IFI RC has an full range resolution of 200 counts, compared to the cRIO's resolution of 143 counts. So the resolution will probably end up with about 75% the resolution, not the 50% I stated earlier. My curiousity about calibrating the victors to wider pulse widths remains, however.