Oh, BTW: 100% precision of the vertices does *not* lead to 100% precision sculpt maps. Sculpty earth (
http://slurl.com/secondlife/Areumdeuli/129/131/125) was generated completely algorithmically so the maps are in theory 100% precise, but there's still a nominal amount of pixel-drift regardless.
This is in part due to SL's 8-bit precision limitation. Some numbers are simply impossible to represent in 8 bits.
[EDIT: clarification on "algorithmically"... it's from the actual satellite elevation data, but I didn't use a 3D modeller to make the model. I wrote a computer program that would translate the satellite data directly into sculpted prim format.]