i am continuing to try every permutation possible, but so far all my Crowdrenders have been slower, in fact, much slower than using my single main machine. i am using today's build of blender 2.80. i plan to try it in 2.79, in case the problem is to do with 2.80.
master: i7 6700K + GTX 1080 in hybrid mode
node: P37 Gigabyte i7 4720HQ + GTX 970M
both machines set to CUDA.
render object: a single monkey with glass shader on a plane.