A likely scenario is all the drivers use P1 for qualifying simulations only and do their race simulations in P2 tomorrow. That would mean no value in backing outsiders for P1 fastest lap.
...but it's a guess.
It's pretty hot here in the South of England at the moment,, (14:20), but it won't be for qualifying at 18:00 local time. I haven't looked at any of the odds but if it's breezy later on it might help Norris.
Perez baulked in P1 but Verstappen was .78 quicker than anyone else. Pole looks like a formality for him. The inevitable cooler evening temperature will hurt the Red Bulls. Any wind would hurt Mercedes and Aston Martin. The biggest surprise was how poor the Williams and Alfa Romeo were. The Alpha Tauri, Aston Martin, Ocon, and especially Ricciardo should shorten odds for a points finish. Ricciardo will fancy a top 6 finish on Sunday.
...but again, it's a guess after 1 session, and the Ferraris were difficult to gauge.