Protecting Workers, I'd add a couple more; it's not smart to be fully dependent on a trading partner or partners for critical and essential products, such as food, tariffs can help ensure you maintain domestic industry. Also helping to control dumping by an aggressive trade partner to ensure a domestic industry isn't destroyed.

Eh, I think every industrial society has independently arrived at something like 36-44 hours of factory time per week (plus overtime up to a max of something like 55 hours) , simply because that's the actual optimum[1]. While tariffs might work for other stuff [2], I think you're right that they can be a narrowly applicable scalpel, but plausibly you accidentally picked a bad example.

[1] Caveats apply. For example more advanced machinery with higher stress may necessitate shorter shifts; while highly motivated creative work might permit longer shifts at times.

[2] Adam Smith -for instance- was mostly against tariffs, though he identified certain exceptions such as national defense reasons.