I will come straight out and admit that I greatly prefer Rhinocam to Vcarve.It ought to be better,considering how much more it costs and it has the huge advantage of working with the file in it's native format.Which avoids having to export to an inherently faceted format.For your current setup,can you adjust the element size of the .stl mesh in Rhino?It will increase the size of the file a fair bit and give you a leg up when importing an already finer file .