Hi Coy,
This would have, and did for GMO, work well back in 2000 when the valuations were so wide, as Bernstein described, “You could drive a Mack truck through them.” (not an exact quote)
Valuations have converged now, so it is a bit more difficult to identify the markets you would be better off holding. As Phil DeMuth (and Ben Stein) put it in their “Yes, You Can Time the Market,” we will not likely see another bubble like the last one in our lifetime.
It has been my observance a more diversified portfolio is not as subject to market valuations as the lesser diversified portfolio. You could set up a market neutral portfolio if you are concerned over this. Phil DeMuth also offered some of these in his other book, “Yes, You Can Supercharge Your Portfolio.”
One of the most simple market neutral portfolios would be something like, total US, total international, REITs, bonds and commodities. These could be held in equal percentages and rebalanced every year or few.
Chin