@ypvs: I didn't mention it because prior to your post I had absolutely no knowledge at all about CUDA. I installed it to my Ubuntu 16.04 successfully using NVidia's instructions and a deb-package. In theory it should instantly be available to Wine. Options in render settings were still greyed out. There is probably some setting I don't know about. I also tried with a wine-staging version 5.0.2-cr2 but was not able to launch Poser and don't currently have any interest to iron it out. Back to running with a working stable 4.0.2 version (no GPU rendering but it's not really that big a deal to me).