A small business jet flying at 0.65m or greater at height will probably be through most wake turbulence before there is any great effect. I have been through it in a small Citation on several occassions and just experienced a minor bump.
It is impossible to predict the severity of any wake turbulence at height. The probably effect of a serious incident would be a high 'g' encounter in the form of a big 'bump' with a possible 'g' overstress.
If an upset was the result the cew should lock the controls and let the aircraft fall out before recovering from the subsequent unusual position once flying speed and control is regained. The height loss or gain is difficult to predict but could be within the 300ft avoiding a level bust or in extreem cases be as much as 1000'. However, as a matter of opinion only, this is very unlikely but not impossible.
A high speed stall is a very different set of circumstances to a wake turbulence upset but one could experience some buffet as part of the experience.
MM