When the bump puts you at 90 degrees to the surface, and your headset is around your ankles, then I would worry about the bumps, untill then realise the aircraft is designed to handle a lot more than standard bumps. It may be uncomfortable but thats what you get for flying light and slow. I find that if I wash 5 to 10 knots off the cruise speed of the Xair (55kts) then the bumps seem to smooth out a bit. As my instructor says, september to april, not happy. May to august, armchair rides (paraphrased a bit)