Oak can be really overpowering in Cider (think Chateau Plywood). One way to avoid that is by adding oak during primary fermentation (as is done for Chardonnay).
If you go the bourbon soaked cubes way, you have two choices: add the cubes (a few and taste-test regularly) or you even try adding the bourbon (which will have an ever bigger oak taste) 1/2 oz at a time and taste-test.
MOD EDIT: Sig only takes up 6 lines now. Fermenting: Apple cider x 2, Doppelbock, Red, Oatmeal Stout, West Coast IPA x 2
Bottle conditioning: RIS
Keg conditioning: La Fin du Monde clone
On tap: Maudite clone, Double Munchen, Oktoberfeast, Oktoberfest Pilsner
Planning: Brewed in 2011: 22 (2010: 15, 2009: 29, 2008: 21, 2007: 1)
Wine made in 2010: 6 kits (2009: 19, 2008: 30)