2006 Cummins 2500 Leveling kit

hows it going, I recently bought a 2006 Dodge Ram 2500 cummins megacab and is six speed manual.

My question is I just bought a rough country 2.5" spacers for a leveling kit and im going to replace my shocks with skyjackers and im wondering what size it is I need.

can someone possibly put me in the right direction so I can order online

Thanks Coady