I am a lapidary and gemstone/jade carver and silversmith and I would like to tackle engraving and add it to my abilities. I am curious about the differences and usability between the different GRS models like the Graversmith and Gravermax G8? I want a machine I can grow with and would not soon wish I had bought a more professional model. I would love to find a good used setup but I just never really see them. What's good but not too outrageous? Thanks so much!