The gridding algorithms are quite different in V17 compared to V14.8, so many options simply do not have a one-to-one conversion. The best strategy is probably to learn how to use the gridder in the GUI of SEMCAD 17 (in particular the Manual Grid Settings) and then use the "To-Python" function to auto-generate the corresponding Python scripts.
I don't know V14.8 well enough to answer your other questions from the top of my head and my current V14.8 installation is acting up, so I can't help with your other questions right now. I will as soon as I fix my setup!