Grob,

Sorry can't answer the Dotan question.
However it is not that hard to make your own from carbon.
If you make the stocks to match the rudder heads and before assembling the stock lay the inner face up over a sheet of plate glass and apply the same finish to the heads of the rudders you can get very low friction between both the head and stock with absolutley no play. When you get this it is a snack to set it up so you can pop the rudders from your normal sailing position at high speed.
Works for me.