I raised a qustion about consumer grade GPS height accuracy in this thread: GPS height accuracy?
(good grief, is it really that long ago?)
It has occured to me since, that although the absolute height accuracy is not great, relative accuracy might be useful eg if you visit the summit and note the height reading on your GPS device, is it safe to assume that readings showing a difference down to 25m lower are reasonably accurate? You would of course have to keep in mind the other rules concerning intermediate cols etc.
This doesn’t answer Andy’s question, but it might be a practical solution when a visit to the summit doesn’t involve too much of a detour from your proposed activation place. I suppose that for most summits with a very large AZ, it wouldn’t be too hard to find a spot from the map anyway.
73
Adrian
(I’ve just re-read the old thread, interesting stuff - there would still be a height uncertainty for the relative reading, I wouldn’t trust it to the nearest metre or two…? )