[mmoe]

I would use advanced Z level, from the bottom up. Equidistant is great for complex shapes, but it jumps around the z axis way to much and I feel it also creates sloppy Gcode.

I am spoiled though, and have 4 axis pro with the multiaxis toolpaths, which give you far more control over surface work. They also tend to compute in seconds, rather then several minutes.

"Between 2 curves" is probably the most ideal and is part of multi axis as Mike suggests. However, the technique I use for working on round overs with equidistant offset is nearly as good since you establish a drive surface that starts it out in a smooth path, which helps all subsequent paths add stay smooth as well. Z-level can work, but the Z lifts and leadins/leadouts will be excessive on complex shapes with a lot of Z variaton. Really, you have to look at each job with fresh eyes and determine what will suit that task best based on the unique shape it has.