Let me start by saying awesome effort and good methodical way of documenting the result.

However this is the worst time to do the experiment. The values are not at all reflecting general conditions.

1. a lot of folks have the wallets offline due to all the forking.
2. many wallets are stuck no different fork chains when staking is made.
3. Net difficulties is varying from 4.X to 0.0XX making predictibility harder

Place network difficulty in the picture at each of those point and you will see a entirely different story.

I personally have stacking for the first time during this when i had balance ~ 10XX.

I applaud the effort but the values will be highly skewed and this would warrent a retry at some later stage when network at stablized.

I would have personally used this low time to actually gather more GRC's and then push them to wallets once they stabilise to get more stakability like you suggested.