Hello David,
Thank you for reaching out to Plugable support.
I want to thank you for that very detailed diagram you put together, It definitely helped me narrow your options down a bit better.
I think switching to the UD-3900H from the UD-3900 would be a great solution to save space. The main thing that you’ll be missing out on is the integrated audio ports on the UD-3900. Other than that functionality will be the same.
So, in summary, with the UD-3900H, you can connect one of your DVI monitors directly to the DVI port on the UD-3900H dock. Then, with 6 USB ports available (two USB 3.0, four USB 2.0), you can connect two additional UGA-165 adapters for the other two monitors, keyboard, mouse, Seagate HDD, and 1TB external HDD. This would use all USB ports on the dock.
If you have any further questions, please don’t hesitate to contact us here at Plugable!
Thanks,
Omar D.
Plugable Technologies
www.plugable.com/support