I'd expect more than 10 pages if he does well for England; certainly so once the usual pre-match quotes start being twisted by the press to stir things.
30 pages afterwards is a good shout - maybe depends on how he celebrates when he inevitably scores. I posted in the match day thread a quick scale of possible celebrations:
1. Genuine no celebration (e.g. Denis Law)
2. A showy "look how much I'm not celebrating" celebration (e.g. Cristiano Ronaldo)
3. Normal celebration with Arsenal fans/players
4. The full Ince, in front of the Arsenal fans
5. The full Ince, in front of LVG (or Sir Alex if he is there, with added Usain Bolt celebration)
Anything from 3. and above will guarantee a minimum of 30 pages