Okay, I just came across this on Madfientist,
http://www.madfientist.com/roth-ira-horse-race/. I had never heard of this and I'm not sure I completely understand. As far as I can tell, when you want to start converting your tIRA to Roth, you could open a second Roth and move money into both and whichever one performs more poorly, you "give the money back" to your tIRA. Someone correct me if that is not right, but that is what I get from this.
Anyone already using this practice or would try it? It seems like a good way to maximize growth on conversions.