16-18 hour days at work all week...yeah, you could call it busy ;)
as for Probe II, the NB temp has always been consistent for me. when ambient temps raise, the NB temp raises appropriately, and then falls when i drop ambient again. i have no problem believing your temps went down by tightening the screws with washers. did you leave the springs in place or just remove them? might try it when i change the thermal paste as well. also, was it just for the NB mount holes or for all screws you added washers too?
idle temps of course are one thing, but load is another. you probably won't see as huge a drop, or maybe you will. but again, Probe II hasn't done any funky readings of NB temps like it does with CPU. load up the system with
HCI Memtest, and see what temps are. when fully loaded, i have found HCI to bring the most heat to the NB.