Vanguard on tax efficient placement

The Vanguard folks have a good article about placement of various assets for tax efficiency (link). It tends to be of more interest to slow and steady long term investors vs. rapid-fire traders or all-or-nothing plungers.

Where might precious metals fit in? For ETFs like GLD and SLV, they are tax inefficient and would preferably go in tax deferred or tax exempt accounts. For physical metal, I would tend to say in taxable accounts even though the tax rate for those honestly reporting is often at the 28% collectibles rate. The additional paper work to hold physical metals in retirement accounts is a negative. Even though I am an options trader, I often prefer simple, and less paperwork, less tracking is a good thing.