The sculpt map that AC3D exports is always 64x64 pixels/vertices, which Second Life downsamples to 32x32 at high LOD and 16x16 at low LOD. The exporter samples the surface of your model to generate the map so that it has the exact number of vertices regardless of the number--or more importantly, configuration--of the vertices in your model. It performs the scan process in UV space, meaning areas of the model that consume a lot of texture space will get more vertices in the final sculpty, whereas areas of the model that consume very little texture space get fewer vertices.
This thread has some example images that show what I mean:
http://www.inivis.com/forum/showpost...45&postcount=5
Basically, if you scale something up in the TCE, you can assign more vertices to that region.
[BTW: I'm working on a "precision mode" exporter that's less sensitive to UV space.]