I was wondering if you were the author of those blog posts- very good work. I was referred to your work from a Bogleheads thread. You lay out a very compelling case. In fact, I am executing your exact plan with my Vanguard Roths: S&P500 (VFIAX), Developed Markts (VTMGX), Emerging (VEMAX) and short treasury (VFISX), using a 6 month look back. I am following suit with my TSP funds: G,F,C, and I. (I am excluding the S fund with its medium and small US caps due to its volatility and redundancy to the US market in the C fund).
Question: I presume you chose US, developed International, and Emerging for their geographic diversity? I have unfortunately not read Gary Antonacci's book.
For others, if you google Adaptive or Tactical Asset Allocation, you will find academic papers published over the past few years that pretty much lay out other good arguments for this momentum strategy. Like Miles, I am executing the strategy in only tax sheltered accounts for now, but I'm in a low enough tax bracket that I may go "whole hog" with my taxable acct as well, if this strategy proves as valuable as the evidence suggests.