Meanwhile what does social distancing look like on a rollercoaster? 25% loads? 50% loads?
For sure the minimum recommended distancing of 2m doesn't apply when you're moving, especially at higher speeds.
An aerodynamic study of droplet transmission in different activities, suggests that distances would increase at higher speeds, suggesting a running pace in zero wind conditions might be better increased to 10m to maintain a similar level of exposure risk as 2m gives when standing stationary [source
Basing on just this research alone, it would suggest to me that only a single row could operate per train. However, it would require additional and specific research on both the aerodynamics side and the risk of droplet transmission in ride settings, to be able to declare one way or the other whether attractions could operate and maintain a social distancing level of safety.