Are there other stocks beyond BRK that you've had success in applying this approach to predict likely forward return?

There are different kinds of stocks.
Berkshire is in a relatively small category of firms with a relatively steady and extrapolatable value growth trend, yet with high volatility in "blatant" short term results.
The problem here is just picking a suitable type of smoothing, which the top post attempts to do.
Just enough smoothing to get a relatively stable line--
but not enough to let the level of the trend line be too out of date compared to recent business results or to let you erroneously count on a given growth rate lasting longer.
The metric you use can vary a lot--earnings are most common, but for other firms the better metric is cash flow or book or sales or (rarely) even dividends.
Maybe Alphabet might fall into this category, using sales as the underlying metric (as their net margins are quite variable) and assuming that multiples will fall gently over time.

Other categories of firm it wouldn't be much use.
Some firms are relatively predictable--relatively steady progress in some obvious metric.
For those, you don't really even need an smoothing. Sometimes a simple P/E will tell you what you need to know. Think of Costco.
Is the observable range sensible given the speed of value growth, and is the current multiple higher or lower than its historical average?

Some firms have volatile short term results, but the overall trajectory of the firm isn't that predictable so smoothing won't help you.
Commodity firms will always track the unpredictable pricing cycles of the commodities in question, so smoothing will mislead.
Some firms really too much on very big concentrated bets, say Softbank or Fairfax, so smoothing isn't much use.
Some are at the mercy of unpredictable fashion whims, like Crocs.

And lastly, some firms look at first like steady growers but their business model is headed for a cliff.
The Schumpeter type, where stability leads inevitably to instability.
This often includes roll-ups, firms massaging their earnings, and fast-growth concept restaurants or specialty retailers.
Or fad-like tech firms riding a trend you know will end or at least top out.
Beware any bank-like entity growing much faster than the economy it serves.

The best source for ideas on this pick-a-metric-and-smoothing approach to mean reversion investing is probably Ned Davis.
They have a book, now somewhat dated, that shows the best metric to use and its range of multiples over time for many large cap stocks.
This is included in some of their services, though it's too expensive for most individuals, including me.

Jim