Santha (Spectra), Ultra or Cosmos

I have a Spectra 10 - modified for chocolate making from chocolatealchemy. This works great for chocolate making but has a bearing in the centre of the granite base which leaks a little grease on occasion.Recently I have been able to see how Ultra put theirs together and they have a clamp down arrangement, so their is no bearing in the chocolate.Has anyone tried or used the Cosmos grinders, do they have clamp down or a bearing in the centre of the granite base? Has anyone tried them for chocolate making.