Central question: How do you want Nader votes treated?
Good question. Incorporated to the extent that they are 'Democratic' but dissatisfied with that particular Democratic candidate and/or enamored with Nader's cult of personality. It's hard to say exactly what I mean by this, I hope that's an adequate explanation. It's like if Huckabee ran as an independent and did well in the South, it wouldn't necessary show a shift away from Republicanism overall.
I'm really leaning towards identification over registration but of course the latter is more easy to consolidate into factual and convenient numbers.