It's in the POH. Mine is 1.3g. Most modern AP deal pretty well with turbulence, anything that I sit and think oooh this is bumpy in I will disengage and hand fly.
The key thing here is that the AP is really good as an enroute tool and when in the airways mine is on all the time. But it has to be remembered that most of the time the reason I am in the airway is to get clear of cloud.
For the IMC pilot relying on an AP as crutch it opens a whole can of worms for discussion.