PMs aren't an investment imo.
They are a redundant backup.
Anyone who wants to actually build value shouldn't be looking to PMs.
PMs are great if we want an oh-shit button in play during a banking crisis.
But they are worthless unless you Physically own them.
I personally like silver better than gold, but both are good hedges.
An appropriate amount would be 1%-3% our net worth into PMs.