i ran into the same sort of documentation desert.

off the top of my head:

- keep in mind there is LVM and LVM2, and proxmox now uses lvm2

- I don't understand the thinpool allocation. You don't have to use lvm-thin if you don't want to deal with oversubscribed volumes, or don't care about snapshots or cloning storage.

- get to know "pvesm". A lot of things you can do in the gui

- when making linux VMs, I found it easier to use separate devices for the efi partition and the linux partition, such as:

  efidisk0: local-lvm:vm-205-disk-0,size=4M
  virtio0: local-lvm:vm-205-disk-1,iothread=1,size=1G
  virtio1: local-lvm:vm-205-disk-2,cache=writeback,discard=on,iothread=1,size=32G

(virtio0 = efi, virtio1 = /)

and I can mount/expand/resize /dev/mapper/big2-vm--205--disk--2 without having to deal with disk partitions