Chess: How great a materiel disadvantage for a grandmaster to be at even odds against a novice?

[pulykamell]

Relevant recent-ish thread here:

Chess: handicap by Elo

So Wikipedia has a handy chart for handicapping chess games. However I cannot seem to find one relating to both players Elo rating. For instance one handicap is a knight removed, what should the Elo rating difference be for this to be fair? I’d venture to guess between higher level players the range would be much smaller. For my friends and I we’re looking at 1100 to 1600.