Getting back on topic, the number of weeks the orthodox PP has had a negative sequence of returns is 107.6. Let's round it up to 108 for dollar cost averaging purposes. So if you had $100K to plow into the PP, set up autodeposits (and autoinvestment) for $925.93 every week until you are fully invested. You can sleep at night with this one, budd!
Also, I just noticed that rebalancing annually is actually riskier in terms of MaxDD than using the close equivalent of 30/20 bands. However, the P2T backtester uses absolute not relative percentage bands, so I cannot test them out on the Risk Parity PP which is stuck with annually (it does beat the orthodox PP rebalanced annually).
The best bands in terms of reward vs risk for the orthodox PP is actually 40/10 not 35/15: 8.98% CAGR, -19.83% MaxDD. I believe that if we were able to optimize the band percentages used, we would arrive at superior end results.
BTW, the Risk Parity PP outperformance over the orthodox PP is only marginal (<.50% CAGR, several percent less MaxDD). Is it worth the trouble? I think it depends on how much gold's unbalanced risk contribution bothers you and whether or not you want the ability to construct a PP portfolio with a specific risk target in mind. It certainly makes the most sense if you're going to dump cash and do the three assets for higher growth, especially if leveraged. It could also make a difference between transaction fees eating away too much terminal wealth and not.
However, given the difficulty of knowing exactly which bands to use with the Risk Parity PP and the inferiorness of annual rebalancing vs bands, I will defer to the available data at the moment and not speculate.