I am looking at a coring system for my Jet 1642. I am considering the Oneway and Woodcut. I don't often turn larger than 10-12 inch bowls. I understand that the Woodcut does not offer flexibility of shape. I am not clear how the Oneway would allow different shapes. With the Oneway, what would be the best size for my lathe? Would the 12 inch allow me to do anything 12 inches and under? Is this measurement the outside of the cored cut meaning I could leave one larger on the outside, maybe 14"? That sounds adequate for my lathe. What am I missing?