The first question is what the metals are meant to do.
The first question is not what another investor holds. It is what job the metals portion is meant to do. Some buyers treat gold and silver as a hedge against inflation. Others hold them as insurance against a banking or currency event. Still others use metal as long-term savings outside the paper system.
A small hedge and a reserve-style holding solve different problems. The buyer who wants a modest diversifier may hold five to ten percent. The buyer building a reserve against systemic risk may hold twenty percent or more. The number should follow the reason.
Within the metals portion, gold is usually the anchor: steadier, more liquid, and the metal most central banks hold. Silver can add lower unit costs and more cyclical upside, while platinum and palladium play smaller industrial roles.
Many buyers begin with a small position to learn the products and handling, then build toward a target share over time. A Self-Directed IRA can hold IRS-approved gold, silver, platinum, and palladium at an approved depository. The tax treatment follows the IRA type.