Maybe Wiggins can play it by ear. See how he feels to Covatilla and how in contention he is able to remain on the rather non-Wiggins-suited finishes in San Lorenzo de El Escorial and Valdepenas de Jáen, and where he lies GC-wise after the Salamanca ITT. If he's in a good position there, then why not have a go? If he's not up at the front, then pull out and focus on the Worlds.
Working hard until the end of the Vuelta didn't exactly harm Cadel Evans (3rd overall) and Joaquím Rodríguez (8th overall) in 2009 at the Worlds, did it.