To be honest, it's so much easier and less time consuming to get a Pokemon to like you, and Return has the exact same maximum power as Frustration does.
The fact that your Pokemon will like you more just by walking around means you need to constantly feed it herbs or leave it in the PC box permanently for Frustration's power to be maxed, whereas when your Pokemon is at its happiest, you don't have to do anything to keep it at that stage apart from keeping it from fainting.
As for how many herbs need to be used, I'm not entirely sure because there is no such item called "bitter herb" - it's Energy Powder, Heal Powder, Energy Root and Revival Herb that are the specific items. They decrease happiness by different amounts:
>Using EnergyPowder -5
Using Heal Powder -5
Using Energy Root -10
Using Revival Herb -15
And to know how many you need, you need to know exactly how happy your Pokemon is. That's more or less impossible unless you kept track of how many steps you've walked or you just caught. If you just caught it, it will be at base 70 happiness, which means that it will need 7 Energy Roots to make it hit 0.
Bulbapedia - Friendship