I will describe our experiences with SM#331 and assume that you have similar equipment.
In the conditions you describe, we have found that you need to switch the autohelm drives to the linear drive that operates directly on the rudder quadrant. This unit seems to respond faster than the chain driven / wheel mounted drive unit.
Next switch the "response" setting on the control unit to a "high" setting. Whenever this unit is turned on, it automatically goes to a response setting of "5". In light winds or motoring I will typically set the value to perhaps "2". When maneuvering in tight spaces under autopilot control, I use a fast response setting, such as "7" and will set this to maximum under the conditions you describe. You cannot make an autopilot anticipate a large wave but you can at least have the steering respond quickly to avoid getting into a broach situation.
I have run with goosewinged main and poled Genoa with 30 knots from the stern but under these conditions there is no stiffening component in the wind to damp a side to side roll. For this reason I may de-rig the pole if I feel there is a risk of submarining the pole-end on a roll. With a really strong wind you will probably not need the pole anyway, in order to hold the reefed Genoa in shape.