Static HDR's are easy but I still can't crack them when there moving objects in them.

Currently working on an early morning exterior pano that was shot at -2, 0, +2. PTGUI can't cope as there's just enough movement to confuse the cp generator. I've output three separate panos and have layered them in PS3. Trouble is I'm struggling with the best method to erase/mask/filter/etc the layers to bring the sky back in and remove the ghosts.

I did come across some articles on this a while ago but can't find them now. Can someone put me out of my misery?