Install DSON, and V6 into a new external runtime/library?  That way if I don't like the results, I can uninstall DSON and remove that library?  I have a lot of V4 content, not sure how much I'll be able to use with V6.

To answer your original question, yes, this is exactly how I have mine set up; Install the DSON Importer into the Poser Program Directory, and install V6 and the Genesis 2 Starter Essentials (both DSON Core and Poser CF )into a folder, and add it to the Poser Library.  I have my Genesis 1 and Genesis 2 figures and clothing in seperate Runtimes; However, DSON clothing seems to somehow need to be in the runtime with the figure to work properly.  There is some good free clothing for Genesis 1 and 2 floating about. Much of it will work in Poser using D3D's free DSON foader script, which loads items that don't have Poser Content Files...

http://d3d.sesseler.de/index.php?software=poserpython&product=dson_loader

Thanks WandW, sounds like I can try it out without much issue.
Jura, I already bought Octane, about a month ago, which is only a few weeks before they announced the new version.  Figures.  But I have Nvidia cards so that is not an issue.