They look interesting. When designing lovely graceful ships like this for space, I would try to remember that in space, ships can have really exaggerated proportions, you could really exaggerate their gracefulness and it still be believable. For instance the case of the Canadarm used on the space shuttle, it works perfectly well in space, but is completely not functional on planet. So if a ship were using solar sails you could have sails that absolutely dwarfs the actual habitable structure, or you could have an absolutely giant enclosed hanger if it were mostly empty space. The physical forces needed to be considered in space are the structural integrity as it relates to acceleration, deceleration and rotation.