It's not unworkable or inconceivable if every country in the world is in agreement and everyone abides by the same regulations and everyone was on a fairly even playing field, it works in the EU and there are no customs or duties to pay within the EU.
One of the Davis/Gove/Johnson trio, can't remember which one, said that the tariffs would pay for the increased government investment in the NHS etc but the tariffs are paid by the importer and thus the consumer.
There's no advantage to Stan because someone who can produce it much cheaper somewhere else will undercut him.