self-sufficient person for exercising treaty rights !!!

Hi folks ..

I've got married to a spanish national recently. I'm a non-EEA national, and we are moving to the UK in few months. Obviously, I need to get an EEA family permit, however we are asked to prove that my wife is exercising her treaty rights beforehand. She's a fresh graduate and has no job offers, so we think of self-sufficient person to exercise her treaty rights.
We are wondering if anybody has got any experiences ? And what's the appropriate amount of money should we put in her account to convince them?

Thanking you in advance for your responses.

See also 21.2.4 Self-sufficent person