Here we have a simple plywood disk mirror cell in the mirror box. there are 18 felt pads at the calculated points for support of the mirror.
Here I’ve cut out two 30″ diameter altitude bearings and matching rocker box sides from a single 2’x4’by3/4″ sheet of plywood.
Here we see the altitude bearings attached to the mirror box, resting on the rocker box with the mirror resting on its cell.