These bearings seem like a big improvement over what we usually have to do for the unstayed rotating masts.  In the past builders have had to machine a bearing out of a giant chunk of slick plastic.  Most of the plastic was ground off and wasted and the cost ran into thousands.  http://www.glidebearings.com/

Spherical bearings like the Tides units would have been perfect, but were not nearly large enough.  Bendy materials like carbon fiber require spherical bearings to keep from binding under load, or as Rob Denny does, have a very loose fit.

These kind of are of the loose fit variety.  I see the bearing having a fairly close fit to the round mast, but deflecting with the mast.  I have not detailed this yet but will.  The bearing will need a fiberglass sleeve around it to protect it and keep it round.  I see this whole unit captured in a looser fit.

Contact Tim Creighton at Glidebearings  tim@glidebearings.com