Is composite *coverage* the lever for the player-strength offset? (No)

The fitted-α note (2026-05-29) closed with: "the real lever is coverage, not coefficient form: the offset will only ever touch WC-vs-WC fixtures until the player composite is extended beyond the 48 qualifiers." The player composite (data/wc2026/team_composite_sum.csv) covers only the 48 WC2026 qualifiers, so the Model-16 offset Δ = α·(comp_home − comp_away) fires on just 228 of 1 926 holdout matches (11.8%), one walk with n=2. The claim: more coverage would let the offset (and/or a…