The split
Two tiers with different jobs, sharing one scale.
The four core engines are the ones the strategy's definition of a continuation depends on: structural position, momentum acceleration, participation, and trend strength. Remove any of them and the concept being tested changes. The two optional filters are different in kind — EMA alignment asks whether the multi-timeframe gear structure is stacked in order, and the ATR slope check asks whether volatility is expanding into the move. Both describe the quality of an environment that the core four have already identified. Neither defines it.

