This is a slightly updated article that addresses early buys breaking a downtrend.
Portfolio Management Can Be Effective With Pyramiding | Investor’s Business Daily
Basically, 50% of your allocation at buy point (traditional buy or break of downtrend in the right side of a base), then 30% after 2% into the zone, then 30%.
They state your second and third buys could be after a tight consolidation like a 3-weeks tight or a small shelf.
Short and easy read, I recommend it.