Transfer a Macintosh hardware installation to Parallels Desktop virtual disk

Setting

a slowly dying macintosh needs to be virtualised to be kept alive

Prerequisites

a Macintosh (Mac Mini late 2009)
another Macintosh (iMac 5K 2017)
Parallels Desktop v15 (later herein only refered to as PD)
a bootable stick (to create the bootable disk in Parallels)
a TimeMachine backup of the Mac in question (here Mac Mini) on an external hard drive

steps to be taken

create a TimeMachine backup of the mac to transfer on an external disk
copy additional file to this disk if needed (i.e.: when using Little Sntich -> export Rules !)
install PD
create the bootable stick * (see https://carlothecat.chickenkiller.com/gist/create_a_bootable_installer_disk_image_from_InstallMacOSX.dmg)
create a new virtual machine in PD (adjust # cpus, ram and disk space according to your needs)
start that up using the stick as boot medium and install macos
during setup migration assistent will show up: use the external backup drive here
after reboot install Parallels Tools !
proceed with the aftermath if neccessairy

the after: fixing any glitches after migration

see: https://carlothecat.chickenkiller.com/gist/control_visibility_of_system_menulets_via_terminal
if desired adjust the following if your hardware requires that:

excerpt from ~/Library/Preferences/com.parallels.Parallels Desktop.plist extracted with plutil -p:

--------8<--------8<--------8<--------8<--------8<--------8<--------
  "Console.{63f779b4-da02-4206-b081-b75bff03e66b}.0.0.Window Frame Geometry" => "@Rect(14 35 1920 1238)"
  "Console.{63f779b4-da02-4206-b081-b75bff03e66b}.0.0.Window Normal Geometry" => "@Rect(14 73 1920 1200)"
-------->8-------->8-------->8-------->8-------->8-------->8--------

NOTE: how to write that information into the plist file ?