Daft question but are you advocating betting in the Overs / Unders market or the handicap market for these?I was told years ago in a training class that "there are no stupid questions", but the trainer had apparently never met Stewboss :) I'm just kidding. It's good practice to look at other possibilities.
On double digit handicap spreads, there is no obvious edge with the split over the last three full seasons (and 2015) 51.6% to 48.4%. Going back to 1995 onward, and it's even closer at 49.2% to 50.8% over 3,929 events.
On the rare 'very' large spreads, those of -17.5 or more, there is an edge in backing the big favourite to cover the spread, but since 1995 there have been just 64 such opportunities resulting in 38 wins, 26 losses.Since 2005, these are 16-11.
Strangely in the five seasons from 2008 to 2012, only 2010 saw any selections, so you would need some patience to follow this, although last season (2014) did throw up a whopping nine selections going 4-5. The Golden State Warriors were the big favourite in six of these (2-4), and have also been the selection twice this season already (0-2).
So my suggestion is to look at backing the Unders in the Totals markets on games where the handicap is large.