That is interesting. With the action set identically on both guitars (measured with a steel machinist's ruler) I carefully measured string heights on both guitars from the bottom of the strings to the top of the body, at several places along the body. Each time they were identical to within a fraction of a millimeter. I even measured directly at the bridge because I've also heard that Edwards usually have higher bridge settings than Gibsons - everything was the same. I re-checked it again after I changed strings and re-set the action and intonation and again, the same.
But I did notice that the Edwards bridge "looked" higher because there's no lip where the bridge posts insert into the body and the thumbwheels on the Edwards are quite a bit thinner than the Gibson. That means you see more threads of the bridge posts showing on the Edwards and it makes it look like the bridge is raised higher up - but in my case the measurements clearly show that it is not. I assumed then that the idea that Edwards have higher bridge settings is just a myth based on that "illusion".
Perhaps we're seeing variations in manufacturing by either Gibson, Edwards or both. In any case, it certainly can't be concluded that Edwards necessarily have higher bridge heights than Gibson - mine doesn't. And the other Edwards I've seen appear to have about the same bridge height settings as mine with similar action, so I think my Edwards is fairly typical. Perhaps my Gibson has a steeper than typical neck angle for a Gibson? After all, outside of certain models, Gibson has been using the rocker style neck joint and that is designed to allow adjustments of neck angle during manufacturing. Personally, I think Gibson is the one with greater manufacturing variations and Edwards probably originally modeled their neck angle off a Gibson with that same angle.
Another thing that has to be considered is body thickness all around. My Edwards is 2.0" inches thick everywhere around the body, but my Gibson is slightly thinner towards the neck than the rear (by about 1 mm). That affects how the Gibson lays on its back as compared to the Edwards and could make the neck angle appear different if it isn't accounted for. It could be variations in body thickness, not necessarily neck angle, making them lay differently on that table.
I also noticed in his review that he said his Edwards was more resonant than his Gibson. I found the opposite - the Gibson slightly more resonant than my Edwards. It's not by a lot, but definitely in the Gibsons favour. His Edwards might have been more resonant because his Gibson is lighter than his Edwards, mine are both the same weight to within a few ounces.
Interesting stuff.