I think this is the best number you're going to get here, though I could be mistaken.
Heat are well rested, and the Spurs aren't the best matchup to slow Miami down defensively. These are the No. 1 and 3 scoring offenses in the league so far. Both teams averaging over 100 PPG and shooting right in the 47-48% range (again, Top-5 in the league).
I don't see much defense being played here. At the very least, 1H over is worth considering. Only concern is if the Spurs are getting worked over, they may fold. I don't think that will happen, though. I think the Heat win 105-98.