I also added a touch of gore to one of the standing stones to encourage proper looming and foreboding. Can't have standing stones without some proper foreboding.
I'm rather happy with what was, after all, a very simple build. While researching it I found again Tacitus' description of the Druidic sacred groves that were burnt by Suetonius on Anglesey.
"Interlacing boughs enclosed a space of darkness and cold shade, and banished the sunlight from above. ... Gods were worshipped there with savage rites, the altars were heaped with hideous offerings, and every tree was sprinkled with human gore. On these boughs ... birds feared to perch; in those coverts wild beasts would not lie down. ... Legend also told that often the subterranean hollows quaked and bellowed, that yew-trees fell down and rose up again, that the glare of conflagration came from trees that were not on fire, and that serpents twined and glided round the stems. The people never resorted thither to worship at close quarters, but left the place to the gods. When the sun is in mid-heaven or dark night fills the sky, the priest himself dreads their approach and fears to surprise the lord of the grove."