Create Virtual Machine with virt-manager

Create a new VM with Windows 10 install ISO
16 GB memory
6 CPUs
Custom storage, VM Storage Pool, 500 GB qcow2 disk
Network: NAT

Customize configuration before install:

Firmware: UEFI
Switch disk to virtio
Switch NIC to virtio
Disable NIC for Windows install
Remove console device
Add a second CDROM device with the Windows VirtIO driver ISO
Set CDROM device 1 as primary boot device

Then go through the Windows install procedure, making sure to load the VirtIO storage driver from the second CDROM device.

Passthrough GPU w/ Looking Glass

Add PCI Host devices for dedicated GPU and GPU audio
Add an IVSHMEM device for Looking Glass, with the correct amount of memory for the display setup:

<shmem name='looking-glass'>
  <model type='ivshmem-plain'/>
  <size unit='M'>32</size>
</shmem>

Verify that the Display device is set to Spice
Under <video>, set <model type='vga'/>
Remove the Tablet device
Add a <input type='mouse' bus='virtio'/> and <input type='keyboard' bus='virtio'/>
Disable the memballoon device: <memballoon model="none"/>

Add the QEMU schema to the root <domain> XML tag:

<domain xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0" type="kvm">

Then add the following QEMU options after <devices/> to enable host file sharing via Samba:

<qemu:commandline>
    <qemu:arg value="-net"/>
    <qemu:arg value="user,smb=/home/ian"/>
    <qemu:arg value="-net"/>
    <qemu:arg value="nic,model=virtio"/>
</qemu:commandline>

Windows Configuration

Configure Windows using the built-in display in virt-manager:

Install the VirtIO drivers and virtio-win-guest-tools from the second CDROM device
Install the Looking Glass host application
Install the graphics driver for the passthrough GPU
In mouse settings, disable “Enhance pointer precision”
Download Custom Resolution Utility and add a custom resolution equal to the size of the Looking Glass client window.
Map a network drive to \\10.0.2.4\myshare to access the host shared folder