Yeah that's the issue, I am able to get roughly what I need by using the fit spline option, but that provides more deviation between the STL and my solid body than I'd like. I suppose an ideal case scenario would be to somehow extend my surface from the post above, to something like the 'fit spline' surface below. That way I'll be able to intersect it while maintaining staying true to the original STL. Any ideas how I could go about doing that?
Also, what do you mean by working with the faceted tool set?