I use HM as well. Last year I did not do guided reading consistently each week. I really saw a lack of improvement with some students, so I went back to groups each week. I find the leveled readers to be hit or miss. So in the spring of this year I introduced chapter books during guided reading rather than the leveled readers. The students were much more interested and I could still address the weekly skill during my groups.
I also use a menu rather than work stations. My teaching partner and I often use some of the language activities from the anthology for student choices. Our menu idea comes from Laura Candler.
This wiki has been very helpful to me this year. It has some brochures for each story. I am not sure it is the same as Diamond Girl. I sometimes adjust the questions to match our state and district testing.
I am glad you asked this question.