[virt-tools-list] Problem accessing USB devices under a VM running Windows 10

[Jeffery Small]

I'm following up to my last post of just a few minutes ago.  I discovered
the nature of the problem: user confusion.  After reading many articles on
the subject, I thought that using the virt-manger option to "Add Hardware"
was the trick to getting USB devices attached to the VM OS.  After posting,
I discovered the menu option:

    Virtual Machine->Redirect USB device

which offered the option of attaching all USB devices visible in the host
environment.  Once I found this, it was an easy matter to attach one or
more flash drives and have them appear under Windows.

I did me additional testing and discovered that it didn't matter whether
the USB devices was first added as hardware or not.  So adding it seems
pointless.

So now, I have a couple of new questions.

1)  Every time I restart the VM I have to manually redirect the external
    USB device.  When I install the USB key I will want it to redirect
    every time so that it is always visible to the software.  Is there a
    way to make this redirection permanent across restarting the VM?

2)  I had previously discovered that, using "Add Hardware," I could only
    add one additional USB device.  The same was true attempting to add
    an additional USB Redirector.  In either case I would get the message:

        "Error adding device: internal error: No free USB ports"

    I currently have the following four redirectors:
	USB Redirector 1  (Type SpiceVMC)
	USB Redirector 2  (Type SpiceVMC)
	USB Redirector 3  (Type SpiceVMC)
	USB Redirector 4  (Type SpiceVMC)

    Just for my own understanding, is it possible to increase the number of
    internal USB ports for the VM so that additional hardware and redirectors
    can be added?  If so, is there some documentation on this?

As always, thanks, especially to Christophe Fergeau for his previous reply.