At this length of time I dont recall turbulence affecting the periscope view. In any case turbulence of any severity would quickly lead to refuelling being temporarily suspended, as losing a probe in these circumstances was a real possibility. Never once affected by airsickness in nearly 6 years on tankers, but as the only time in my life I ever had to use the paper bag was after over-indulgence in brandy on a British Eagle Britannia trooping flight, I'm probably not the best person to ask!