Macbook pro to display and cintiq

[@nge!]

Have a Macbook Pro connected directly to a Cintiq 12wx graphic tablet via miniport display.

Would like the option to add an additional display (probably a Samsung LCD) via USB to VGA adapter. Plugable USB3-VGA USB 3.0 to VGA Graphics Adapter. Is this a good way to go? would there be a forseeable effect on the Cintiq sice it would not be connected to the adapter?

And one final, admittedly ignorance rooted question: Would the statement "the Products based on the DL-3xxx family are not currently supported on Mac OSX."
mean that the product will not work on the Mac or the the company will not offer support should you use the product on a Mac?
\thanx