I had a good deal of luck doing the Nesingwary quests in Valley. Got probably about 5 or so in the span of an hour killin' critters.
I have 10 SoH and I have no idea what to do with them. I could make more imperial silk, but I'm already sitting on like 8, have both epics, and at this point it kinda looks like a waste.
The night is dark and full of terrors...
There is a vendor on the Golden Terrace that you can get other items for them - I leveled up my leatherworking this way.
Since they upped drop rate.. you can find them anywhere really...
Just farm a "secondary" thing... Cloth, Meat... "dailies"..
Between getting 16 on my farm,and my dailies.. I usually walk out with 10 spirit of harmony a day. (that I burn into Imperial silk ;d)
kunzen camp in northern valley of the 4 winds. just keep killing the 4-5 packs of rockflingers. I get like 2-3 spirits an hour that way.