Ack! Somehow I screwed up my unsharp mask setting. I was using it at the default settings, but can't remember what they were.
#1
Don't worry about it. The default settings are meaningless. You need to adjust on a per image basis. I think they are 50,1 0 if I remember rightly.
#2
I know the 1 and 0 are correct... but couldn't rememeber the amt was 50 #. I fwiw, i usually adjust the top slider and leave the radius at .6 and threshhold at 0. that's just to add general sharpness. to adjust edges then i start playing with the the middle and lower sliders.
#3