Personally, I'd stick to something like Rhododendrons which will actually form a nice hedge within your lifetime. I have several Canadian hemlock which do very well in quite dense shade and half shade, but after over 30 years, they are about 15 feet tall, and at 10 foot spacing barely touch.

As for privet, I hate it with a passion I generally reserve for deer and other destructive varmits. Reseeds everywhere, and maintainance and dead wood removal gets to be a problem in a few years.

George

You should be aware that the wooly adelgid is attacking and killing hemlocks all up and down the east coast.

Forty years ago I planted a row of hemlocks in a shady spot. Over the years they have become more difficult to trim to control their size. Also the lower branches have died despite my efforts. This past fall, I remove all buth the two on either end of the row and replaced them with Rhododendrons. That and the wooly algedid would argue against hemlock. i also hate privet and would suggest Rhodies.