NaNoWriMo

I struggle with tenses. I like the way past tense reads, but I feel like I can represent emotions better in present tense. So the idea I'm kind of working on is to have the first part of the book (about 50,000 words) in past tense, with the story unfolding in a narrative way (though a little fantastical), and then have the second part of the book (about 20,000 words) more like a stream of consciousness. Clear as mud, right? If you have any thoughts, I'd love to hear them (on the tenses, not on how bollocks I am at first drafts!).