I think it's up to the plants how much you need to feed the set up. If they're using up the nutrients, then you might need to add more nutrients more often.
I think adding them once a week will work in some cases, but I would watch how things are going to make sure your plants are getting what they need. If they're not, then you need more.
Start with the recommended dose, maybe a little less, and then see what you need to adjust along the way.
I've found the Advanced Nutrients Big Bud powder is much easier to control and to use, though, so I think you'll have no troubles with adding this to your setup.