My usual mix was Assam dust, with a little Orange Pecot and one other that I forget. It used to be great until one day, years ago, it just did not taste the same anymore. So these days I just use Tata's Strong Dust. Not the same but I cannot find what I used to have which was fantastic. It went away and I don't know if it will ever come back. The tea seller disagreed with me and said no one had complained.
I don't use any infuser. Boil the water. Put the dust in. After some time filter it out and put it in a flask.