There are no weight restrictions but size restrictions. The seats are tight and the harness quite close to the chest so, for example, a lady that is a bit overweight but has a big breast will have problem, same for people with large ''derrière''.
Meclizine Hydrochloride is known as Bonine in the US, Bonamine in Canada but I don't know the name in UK. It is an over the counter drug and beside being non drowsy it is almost without side effects and one pill in the morning is usually enough to clear you of motion sickness for the whole day.
Personally I worked on private yachts for some years and, even if I was not very sensitive to motion sickness but after one bad day experience I then took one every day when the boat was traveling or at anchor as a preventive measure.
Having read that Mission Space at Epcot was making many people uncomfortable if not sick then I decided to extend my use of Bonine to the days when visiting a theme park and it worked beautifully.
As an added precaution or as a non medicated alternatve you can buy an acupuncture bracelet that you just put around your wrist and press on a specific point when needed. There is an electric version avalable too. I also carry one of te basicmdel with me as a booster if I do feel a little dizzy even after taking Bonine o to lent to my companions that have not taken moton sickness medecine when they start to feel under the weather.
Edited: 12:46 pm, November 23, 2012