BOS or Grimoire?

I love journaling, so as a witch this translates into keeping a tome of my own.  I've been doing a lot of reading and most places consider a book of shadows or a grimoire as interchangable -- you just call it what you want.  There are a couple places that said in some traditions a grimoire is seen as a spell book or instructional book alone.  So, in my practice a book of shadows will be my journal, a place I collect knowledge, spells and experiences.  Then, as I begin to develop my own spells and rituals, try them and settle on them, those will go in my grimoire.  I was reading Patricia Telesco's book on keeping a book of shadows and she was talking about organizing it, etc. and that is hard to do when you are learning and discovering new things.  I think the system I have come up with is really going to work for me.  I will probably also devleop an index for my books of shadows so I can look something up over the years....  This is an exciting prospect for me!