Older Thinkpad for Looking Glass GPU passthrough?

A friend would like a used Thinkpad for a Linux host system and an NT guest. He
wants to pass a GPU to the NT guest for hardware acceleration of typical office
programs with Looking Glass, either with SR-IOV or a dGPU passthrough. NT host
and Linux guest is a no.

Requirements:

  • Thinkpad
  • Cheap (older 4c/8t CPUs are fine)
  • Linux host
  • NT guest
  • Working and stable GPU passthrough
  • 14 inches is ideal, 15.6 is acceptable

Some ideas:

  • T14 Gen3 with Intel 12th gen and SR-IOV
  • T480(s) with MX150
  • T490 with MX250
  • P50 with Quadro M2000M
  • P53 with Quadro T1000

GPU performance is not a factor at all, just adequate 2D acceleration. SR-IOV
seems like a nice option for battery runtime.

I have done a few passthrough configurations so I am prepared to navigate that
maze once again.

Questions:

  • Is there any option that has a known high success rate?
  • Will the external display connection work when GPU is passed through? Or only
    integrated display is functional?
  • Is an HDMI dummy plug required? If so, not a problem.
  • What battery runtime can be expected with light office tasks in NT guest?

Thanks in advance!