• 2.9 baseline — 0.6 × season 2.5 (16 gm) + 0.4 × last 10 3.6
• +0.2 opponent leak — they concede 25.6/game vs a 23.6 league average
• at this ground: too thin to count (2 gm) — shown, adds nothing
• −1.9 wet forecast — averages 1 in the wet (8 gm)
• vs them: averages 0.0 over 7 games — evidence, never summed

Derived, not measured — plain arithmetic over his real games, shown in full. Adjustments can overlap (a game at this ground can also be a wet one); they add simply, and this note is the admission.