This is an interesting picture. It derives from a micrograph from an untreated ferret (my animal # 2, negative 4640, block 18578, 27,900 x magnified 4 x) and scanned and processed in photoshop  using contrast, color balance, dodge and burn only.  While continuing to look for molecules that might be surfactant protein A, the round to hexagonal objects with a central density appeared sometimes to be closely linked with ribosomes at the edge of the RER membrane when the occasional opportune tangential section of an intracisternal body in a type II cell is achieved.

These round SP-A? molecules are more prominent in guinea pig micrographs, but this array along the growing edge of a profile of RER was particularly nice in that several adjacent ribosomes were adjacent to several round-to hexagonal profiles of what might be protein product.

I have highlighted the ribosomes and round structures in blue, put a red arrow pointing the a ribosome, a light red line around one such round to hexagonal structure (left in the figure below) and also shown a blue box around the original cisternal body and ribosomes (photoshopped only with contrast and brightness) (right in the figure below.  The relative sizes: ribosomes, approx 20 nm, the hexagonal structures about twice that.

Most publications give the SP-A molecule as being around 25 microns…. i think if the “bundle of flowers” typically assigned to SP-A 18-mer were to spread out at the head… that the dimension when seen from the top could closely approximate the dimension found here.  Each ribosome can be used as a guide to magnification.