Anyone do any "twin studies"?

[Grim Tuesday]

I was repotting a N.B.S "Dendrobium Chocolate Chip" yesterday when I realized it is actually two plants! They had clearly been growing together since compot, and each had the same number of growths, leaves and about equal root systems. I decided to put one of them in S/H and the other in bark to see which they actually prefer under my conditions. I'll try to keep them right next to each other at all times; the bark one will get watered every week like the S/H one. I'm very curious to see if one of them will thrive more than the other. Of course, I will have to wait years for the result of this experiment. And the results will have to be interpreted in the context of this plant in my conditions. Hopefully I'll remember this thread when a conclusion is clear...

But it got me thinking though, I'm sure others have tried this experiment before, right? What plants did you try it with, what were your conditions and what were your results?