I guess it depends on how you intend to use them, and what the exchange rate for those goods would be. Smaller “denomination” would be best if you need to buy food with them, assuming people would part with food at any price. Though with the right tools you could be like an 1849er and slice pieces off of silver and gold bars and weigh them out. Going back 1000s of years, from Rome to the Ottomans, people were known to shave a little off their coins too :-) So you could scam a few people who don’t have the old fashioned balance scale.
Others probably mentioned, however, you will have to be careful about where they are stashed and be prepared to defend them. In a less than total SHTF scenario, think about the old west or any of those zombie shows. You’ll have to find and protect your metals, barter for them, and be prepared to shoot someone in the saloon. You’ll need to be able to hunt for food and maybe team up with trusted compatriots to ward off other tribes.
That’s why modern coins of precious metals have a reeded edge. Shaving can be easily detected.