Settings for engraving greyscale, vectors and cutting on for SM2

I have tried different combinations of power and speed to engrave on 4"X4" 2mm plywood. My laser is focused properly. The images come out mostly B&W with little to no gray areas and cutting is not happening despite 8 passes. Anyone has a fail safe list of settings for engraving (greyscale, vectors) and cutting using Lightburn?
Thanks in advance,