I just don't think Kalu is good enough on defense to play the 4. The sacrifice on defense wouldn't make up for the improvement on offense. Maybe you can have Lakhin (or Ody) at the 4, Kalu at the 5 though.
That said, I am curious who plays if/when Hensley or Davenport get into foul trouble. There will need to be a need for spot minutes at some point. It could be Ody, Kalu or Skillings.
Kalu doesn't have to guard the 4 if he is playing 4 on offense. So putting Hensley out there with him makes sense. But Kalu is very mobile for his size so if it's effort related I hope we can get that out of him.
I would also include the idea of Nolley playing 4 in rare instances of foul trouble. Put Newman in at 3 and Skillings at 2 etc. But I think Kalu can handle the job for 5-10 minutes if needed.