Nowadays it's done in PF, as a 8men group.
Not ideal, but sadly that's how it is, I so wish it'd just pop normally.

You can also just farm potd 51-60, it's not ideal but drop rates are not super horrible and you can queue to it whenever and it's kinda mindless. The max runs Ive ever gone without a drop are maybe 10, but usually it drops every few runs.

That said, I'd surely love if they added more ways to get them. Even just 1 per run in Dalriada.