• 0.2 baseline — his last 10 games; only 3 this season, too few to blend
• +0.0 opponent leak — they concede 38.8/game vs a 35.7 league average
• at this ground: too thin to count (1 gm) — shown, adds nothing
• −0.2 wet forecast — averages 0 in the wet (6 gm)
• vs them: averages 0.3 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.