In designing seasteads we need to understand what amount of motion is acceptable.
The basic problem is that your brain is used to being able to tell what vertical is by looking at buildings and things, but on a ship it is not so simple. The conflict between visual cues, your inner ear, and the motion your body feels causes the trouble.
See 8, Pg. 34 of Seasteading Engineering Report, Part 1: Assumptions & Methodology, by Eelco Hoogendoorn February 2011 for a discussion on Comfort as related to motion.
See Also: Human Factors
In general it seems that after a few hours to a few days people develop "sea legs" and are adapted. If tourists are coming for 1 week visits a few days to adapt takes away a lot of the fun. If a family is moving onto a seastead for good, a few days to adapt is no big deal. Minimizing motion is more important for short term tourism.
Stability of Competition
For comparison here is a very stable $4 million yacht. It was designed by the Dashews and is called "Wind Horse". There are many videos on youtube. It has very large active stabilizers. They have also come out with a $2.5 million version. These boats are efficient enough to cover long distances at reasonable speed. The speed keeps pitch to a minimum and the speed lets the active stabilizers just about eliminate roll. If we can be this stable then we are doing well. If the seastead is a shape that is naturally stable so that we don't need speed and active stabilizers we can have a lower cost and run on solar power.