http://www.cpat.org.uk/walks/nanttarw.pdf . Points out that the cairn at SN 827 247 also has view of PyF as will other points in the area .
Apart from the awful pretend phenomenological nonsense of Tilley and Cummings there have been attempts at providing comprehensive objective studies on the siting of monuments in the landscape. Tim Philips with his study of northern chambered cairns and Tatjana Kytmanow 's on portal tombs come to mind .
A point to raise is I'm, of course, not at all sure what the landscape would've been like in the Bronze Age. Was it the bog it is now, the 'falling in up to your waist' sort of bog I had the misfortune to encounter? If so, why erect your monuments within such a landscape if there wasn't a pretty pressing reason to do so?
The writers of the pamphlet thought it might though ,that's why I mentioned it .
It could have been drier in the BA ,but building sites in what were certainly bogs at the time is not uncommon . Lots of henges and sites like Blackhouse burn seemed to revel in it .