Actually that lead is 44,000. I have seen that 73,000 number floating around but incorrect.
Go here. Go to right side for General Election and click cumulative turnout.
http://nvsos.gov/sos/elections/voters/election-turnout-statistics
I figure with D crossovers at 5% and Is, the magic number to cover here on election day is somewhere around 10-20,000 votes. Is that your take?