I think I would put the OS on the PCIe drive. In my experiences the faster the OS drive the better the system runs. 4gb gets small very quick as well.
Got some more work done on the LCD mounting and bezel. Had to mill a slot into the trim in order to fit the screen proper. It rests in there nicely, just snug enough. Took some patience and a steady hand for this. Now the ABS trim plate will sit just slightly recessed into the factory panel with a cut out all the way around for the screen. I debated a lot about how to do this step, but this is what I ended up deciding on to keep the look clean and factory. I did not want the bezel sticking out or covering the factory opening. The factory trim was only off by about 1/8" just enough to require the slot to be cut. I'm happy with the mounting results. I'll have to file some nice flat rounded sections into the chassis front bottom where the LCD wires will pass to the PCB. Still working on the PCB layout at the moment, but that should progress quickly now that I know where the LCD will be stationed.