Our SOP's state that the PNF must guard the controls below 1000ft RADALT, regardless of whether autopilot is engaged or the PF is flying manually. This means that the PNF places one hand behind the throttles (but doesn't physically touch them) and the other hand on his knee with hand upturned ready to grasp the control column if required.
Seen the autopilot flick off numerous times due to turbulence/shear below 1000' and thats in an aircraft designed only 10 years ago!!
With autothrottle connected, the PF will generally have his hands actually on the throttles as our autothrottle lags behind by up to 10 knots (both fast and slow) and when configuring with autothrottle, can quite easily overspeed the gear.