You gotta remember Webber is an Aussie, Hamelton is a Pom, and aussies are naturaly gifted at beating poms at everything (barring soccer) , And he has the added power of "the jaw".
On a serious note, Webber has a cooler head than Alonso, and would probably deal with it better. Alonso it great at withstanding pressure when he's leading, but if he's behind, all he seems to see is red.
Heidfeld to McLaren wouldn't suprise me, he was brought up through the McLaren F3000 team (or what ever it was called back then), but got beaten by Kimi for the call-up to maccas from sauber.