This micrograph I am using to determine the sizes of the different nuclear structures, so this is the first attempt to define at least four different sizes of components. For me, there is similarity in the size of the granules (beads on a string maybe something like 30 nm) in the cajal body and in the nucleolus. Arrows point to the kind of layered banding parallel strand look of the cajal bodies,  the red circle is about the size of a cytoplasmic ribosome (which would be something like 27nm) and the diameter of the rounded object beside the cajal body (something on the order of 60nm) and an even larger fibrillar component seen through out the fibrillar centers and also just a little above center left (orange spot) which might be 130 – 150nm.  So there are four measurements of fibrillar components in this nucleus, so far.  Will post more.