Also correction to the guide:
You need to leave 5-10% free space in VG in case it’ll be needed to extend pools:
lvcreate -T -l +90%FREE qubes_dom0/vm-pool
Why doesn't Qubes 4.1 use full disk space (LVM)? - #3 by marmarek
Best Way To Resize Dom0 Pool? - #9 by brendanhoar
LVM metadata problem - Free space in thin pool reached threshold - #3 by user-a9dc9a0d