Sorry for the late response on this; I’ll take a stab at it, but Joe might have better insight into this.
I’m almost positive you would cause problems if you grouped components together, and most likely if you switched parts to new layers. Of course, you can always copy parts and put them on different layers, but that could cause problems with the cutlist. Joe is working on some solutions to that problem, however. Joe might have more insight on the layer issues.
As for the VCarve SketchUp import, are you talking about custom parts that wouldn’t normally get exported via the DXF? If that’s the case, you may be able to get away with those parts being on different layers so you don’t duplicate anything. However, SketchUp has a couple of issues with importing parts from a CabWriter model, with the biggest issue being that it doesn’t necessarily know which face of a part should be up. Also, it doesn’t have a way of dealing with grain orientation or part labeling, so I prefer to use the DXF export.
Not sure if I really answered the question or not, but we can keep the conversation going.