If I wanted to make electrum from a stack of silver and gold bars, I would easily chose the macerator over the pulverizer for speed.
Or do what I did, don't auto smelt gold/silver in the first place. In fact gold, silver and lead don't get auto-smelted in my setup. It seemed silly that any time I wanted to make anything that required gold or silver I the mats would be pulverized, smelted, then pulverized again. Since the majority of my gold/silver goes to electrum I leave them in dust form. Since the majority of my lead goes for hardened glass I leave it, too, in dust form. Any time I need them in bars it is small enough quantities that I simply request them from LP, take them out of the project table, and pop them in a blulectric furnace that sits right above my project table. This has two benefits. First, I get the smelting XP and second the blulectric furnace draws its power from my tiny RP2 power net; IE, free power.