I think the second unit should forget about fortifying itself with defensive players and try to optimize the offensive game. For example, no use bringing Scal as a SF, he sucks in that position right now. I like him as a PF though since he can spread the floor well taking a big with him. Sadly our lack of length in the bench doesn't allow the use of Scal as a PF much, maybe playing with Perk or POB.
Then you bring in Giddens and/or Walker since they should have a strong offensive game, plus they can rebound and finish well.