• 1.1 baseline — 0.6 × season 1.2 (20 gm) + 0.4 × last 10 1.0
• +0.2 opponent leak — they concede 64.3/game vs a 56.6 league average
• +1.7 wet forecast — averages 2.8 in the wet (5 gm)

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. Round 4: 4 — far outside his usual range; kept in the average, not smoothed away.