Between foul trouble and "teaching moments", I would be shocked if he got more than 20-25 minutes... That said I think the OP's suggestion of 12 & 8 sound about right, although it does depend on whether they crank up the pace of play... I think they protected Kemba a little last year by slowing things down at times. If they play closer to a UNC pace, then that could definitely go up.
On a side note, Jeremy lamb running off of double screens from AO and AD will be really tough to stop.
Lastly, I am really curious whether JC tries to put Jeremy at PG at times... Imagine how tall and long of a lineup JC can put out there...