Well, I'm back from Middlesbrough Library and I have to say the news is not good for Gordon's method. The excavations of the trilithon holes were not very deep, so the data is a bit inconclusive. However, there is a nice cross-section of one of the outer sarsens. It's the most northerly of the part of the outer circle that is still standing. It looks like the builders dug a ruddy great yaw in the ground and then hauled the stone upright within it. They must have had ropes all round to stabilise it while they packed the area with chalk rubble and earth. If you dropped a stone into that hole it would just fall over again.

Here's a link to the tracing I did at the library: http://www.swifttools.com/Hole.gif (the captions were added after I scanned it).

So, I guess Gordon's claim to fame will have to be stone-rowing after all.

The profile for stone 56 (one of the trilithons) as been known since 1901, see Gowland 1902, see also Cleal 1995. Hope this info helps.