Quote by PAllen
I'll add one more bit to what Peter said. Your stated goal of having tidal effects ignorable guarantees you can't detect Euclidean deviations. Tidal effects are the first order influence of curvature, thus they define the minimum scale needed to detect curvature.

My stated aim was simply to say 'we know tidal effects will matter in practice  but let's fully account for them and just look at what remains'.
...However, if you are willing to span a relatively large distance, and have near mathematically ideal measuring devices, you can detect Euclidean deviation as follows:...[EDIT: as for scale, if you use a 10 meter device near earth, your final deviation would be 10^20 centimers or so...]

Interesting and ingenious but I'm struggling here over principle  goes without saying nothing practical to patent. (caught your post after preparing response to Peter, so some things are repetitive  sorry)