Which other manuscript contain the most Voynichese glyphs?

[-JKP-]

Yes, when y is used at the beginnings of words, it is con, com and its homonyms (and it can also stand alone for these).

• Some scribes used y with almost equal frequency beginning and end.
  
• Some scribes only used it at the end.
  
• Some used it often at the end and sometimes at the beginning (the same general pattern as the VMS position of the glyph).
  
• Some scribes used it at the end and used the reverse-c (which is also in the VMS) at the beginning.
  

I have hundreds of examples of most of these, although the reverse-c was becoming less common by the early 15th century.