Testing the new Octane plugin (v1.10) I've bought. Seems as a perfect solution for similar situations as this one. Did not over tweak it, just a simple Direct Light kernel type setting with HDRI map-based lighting with only 1200 maxsamples. Using response DSCS315_1 filter. Rendered on 2X GTX670-DC2 graphic cards. Took about an hour for 200 frames in HDV/HDTV 70 25 format.