I don't hate Vassell yet but it's pretty clear that he and JC are not NBA starting five material.
I would start:
Kornet (C)
Wemby (FC)
Barnes (F)
Castle (G)
Fox (G)
Sub out Kornet, slide Wemby to C, sub in Sochan to F around the first TV timeout
Sub out Wemby and Barnes, sub in Kornet and Olynyk between first TV timeout and second TV timeout
Sub out Fox and Castle for Harper and Keldon between first TV timeout and second TV timeout
Sub in Wemby for Olynyk after second TV timeout,
Sub in Barnes for Sochan after second TV timeout,
Sub out Keldon for Castle after second TV timeout, if he's playing poorly
Sub out Harper for DV or JC after second TV timeout, if he's playing poorly
Sub out Kornet between second TV timeout and End 1st, if possible, for Olynyk or Bryant
You can usually figure out pretty quickly if DV or JC will be hitting their 3's. Keep them off the floor if they're not hitting shots.