Sure. As long as your compost tea is made with real compost, you can water with it every time you water your plants, if you wanted.
There is no set amount around my house. I foliar feed with it almost every evening in the summer, and use it straight up, to water plants with. You can add some rainwater to it, to stretch it out if you wanted.
I use my own organic compost to make tea with, so I'm not sure what is going on in the world of over-the-counter compost tea blends. I've heard of "boogie brew" (sp?) from a dude on you tube that does garden videos, but I haven't used it myself. I'm willing to bet it's expensive.
You drilled holes in the bottom of your buckets, right?