340 degrees or thereabouts on my compass. Unfortunately I'm no help with the horizon. I'm not really familiar with the area and I had no map with me.
Got the book(s) as well, by the way. Mostly summaries of what's on the ground megalith-wise in the first volume and mostly French stuff which kind of makes sense considering the conference location. Some interesting titbits here and there. I hadn't come across this theory before, though that doesn't mean it's not a bit stale - the capstone of (for example) a portal tomb as the focus of the whole exercise of construction: the veneration of a large rock resulting in its raising to a position of awe-inspiring display. Could have been a part of the story I suppose.