There is very little in the modern jets that is actually covered by the wing anti Ice.
On the Airbus's its the outter half of the wing only.
It is very rare to use wing anti Ice. and techniques on its use are changing again. In order to prevent runback and refreazing the wing are now recommended to be cycled much like the old pneumatic boots. Automatic Wing A/I does that for you on several diff kinds of jets I believe. 3 engine aicraft like the 727 are the exception because they have to run Wing Anti Ice anytime you use engine anti Ice to protect against Ice accretion on the number 2 VHF antenna which then sheds into the number 2 engine.
Engine anti Ice is used anytime there is visiable moisture and from +10 TAT to -40 SAT give or take a few degrees.
Cheers
Wino