You can find the stat "hands" in Expressions Stats. But, I do not think it can be useful for Range Research.Вecause you are getting pool's weighted average values for all stats in the report.
It is not possible to get a total number of hands for Range Research report because it has a very different logic.
Technically, you can add expression stat for a number of hands in your popup, but nobody knows what value you get for this stat in Range Research report.