HI there Cpoco,
I'm in the midst of mine as well. I would play it formally and bring in the personal pieces subtlely, if possible. I don't think pleading or begging comes across well in general, although i hear you on the writing struggle and wanting something so badly.
I would use strong emotion to convey why you are a good fit, and try to channel the emotion into your actual experience past, present, and vision ahead.
Does that help at all?