The Whip's Retort has published a very interesting article on center of mass in marathon carriages. While this may sound like more than you need to know, I found it quite enlightening:
Driving a gig, which has a very high center of mass, I have learned from experience that I can't take turns too fast. People always remark that driving a gig takes a lot of bravery, but mostly it is a case of respecting the vehicle and understanding its limitations. I know I'm not going to be the fastest through cones, so I adjust my strategy and try to find the best route for the gig. This usually involves taking turns slower and tighter.
However, in the marathon carriage, there just might be a false sense of security for some folks. Having the experience with the gig, I naturally drive slower and look for angles. This article made me stop to consider a few things. Of course, there are very many variables involved in any equation and when people and animals are added the results are bound to be incalculable. However, I think this article has value and I hope you find it useful.