The main focus of the design is to build a seaworthy boat which would move in a pattern that would cause the minimum amount of sea-sickness possible. Due to my woman being quite prone to seasickness, I see seasickness as the highest of all the risks why our circumnavigation plans might fail. And because of that, we are happy to sacrifice many other things, such as speed, draft, conventionally acceptable looks etc.
Here is my train of thought:
1) The boat’s design has to minimise any rolling movements, as they are the component which makes the brain seasick. Straight up-and-down movements doesn’t matter, because our brain is perfectly accustomed to them, since it is the same kind of movement which our vestibular system gets when we walk.
I respect a design that states a requirement, then rigorously throws out everything irrelevant to the requirements. Bernard Smith's ideas laid out in "The 40 Knot Sailboat", which eventually inspired Sailrocket 2, would be an example. There was a lot of experimentation between the earliest ideas and the successful vessel, though, and I recommend the same. My own experimentation has led me to discard several ideas that seemed promising when I first thought of them. Most of them were partial successes in that they addressed the requirements I considered most important when I first stated them, but failed on requirements that I had not given enough weight. Practical experience made me reconsider the ranking of the requirements.
The one graph I have seen showing what causes seasickness contained roll amplitude and (if I remember correctly) roll acceleration. I suppose pitch was ignored on the grounds that pitch amplitude is normally a lot less, though pitch acceleration could well be higher than roll acceleration. In your proposed design, pitch amplitudes could be quite large due to the short waterline and small waterplane area, so you will have to consider that.
Further, you might consider what is just about the opposite to your proposal in most respects, an extremely wide and long Pacific proa. In catamarans, the wider the spacing between the two hulls, the smaller roll amplitude and acceleration. A proa could be wider still for the same displacement and amount of materials, and a very low volume ama should let breaking waves roll over without rising much, yet if you give it a large enough lever arm, it would still provide adequate righting moment. I built a radio-controlled model along those lines to test sail balance only, and steering without rudder, I did not test movement in waves:
Models for testing motion could be quite crude, as simple as plastic bottles and a few sticks lashed together and thrown into waves. Compare different beams and hull volumes.
To test whether your concept is at all viable as a sailing vessel, especially one to be steered by sails alone, I would build a scale model, though I note that even a 1:5 scale model would weigh over 100 kg. But if much of that can be water ballast, it should still be manageable.
Another model would be of the interior space. That could be made of the cheapest plywood, and you could approximate the curve with a polygon. If you can find a space where you can build this, do so, then spend a weekend in it. See whether a tall, narrow space is as liveable as you hope. The outrigger will contribute very little to longitudinal stability, so you have to expect the boat to lean forward enough to matter. So try leaning that living space 10 degrees to lee and 20 degrees forward (or whatever heel and pitch angles your scale models assume in equivalent conditions), then spend another weekend inside.
5) As one of my big concerns is if such a hull would sail enginelessly at least as close to the wind as the old square riggers did, I minimise the windage by having a small above-water volume (compared to the excessive underwater volume), which makes this boat to behave almost like a surfaced submarine. I also streamline the pointed hulls and outrigger, and I take advantage of the proa design and make the leeward sides of the hulls absolutely flat and vertical, which will maximise the lateral resistance, as well as giving a hydrodynamic lift towards the windward side.
I think you need to aim for better than that. Many of the old square riggers could not get upwind in rough conditions. See Roger Taylor's account of being embayed on Endeavour II, and eventually being wrecked (
https://www.waterstones.com/book/voyages-of-a-simple-sailor/roger-d-taylor/9780955803505). Also see if you can find the track of Sven Yrvind's voyage in ExLex Minor (
Exlex Minor – Simple habits, simple boat https://www.yrvind.com/category/exlex-minor/) a few years ago. He focuses so much on going downwind in the Southern ocean that he neglects both upwind ability and speed. He averages about 2 knots. When the wind turned he went far out of his way to stay clear of the whole Faroe group, presumably because he could not trust his boat to sail off a lee shore in unexceptional conditions. If that is true for your boat, there will be very few harbours you can approach safely, which is not much good for a cruising boat.
As for the possible benefits of hull asymmetry, the closest you can sail to the apparent wind is the sum of drag angles (lift to drag ratio expressed as an angle) of all the bits underwater and all the bits above water. With a lateral area that large, you probably have plenty of lift already. With a hull that fat, the increased curvature of the windward side may increase your drag so much that your drag angle is larger and your upwind ability worse than if you had made the hull symmetrical, or at least only mildly asymmetrical. I think the Goettingen profiles are arcs of circle and a flat side, so data might be available, though I don't know whether anyone aver tested a wing as fat as you intend. And possibly they have not measured a Reynolds number that corresponds to your chord length and a speed of 2 knots. In that case, you will have to build models, and compare them.
