Multiple smoothing lengths has worked wonders. Now let’s hope we can get a homogeneous fluid at sup-critical temperatures!
Inkscape is not as capable as I’d hoped – it can’t read latex equations directly. (To be fair, there is an extension that does this, but it doesn’t want to play on my system). To import my equations into illustrations, then, I need to output postscript, and use gsview to convert it to paths. A little more manual that I was hoping, but acceptable.