Hi Joan! I have a similar situation. I have more time than you, but have a bunch of mandated things that need to get done that take up time. I came to the site a week or so ago and started searching for the answer. My initial thought was to just give them 2 choices a day, but since I didn't do the research to write the book, I was afraid of messing up the whole Chi of the system by doing that. Well...somewhere on the CAFE site is an article written by the sisters that talks about how each class and grade level is different. Just as they revised the Daily 5 book to have only 3 rotations now, they also said in the article that some classes may have to only do 2 rotations. I think you have to do what you have to do. It may not be your ideal literacy block, the one you had in your head before school started, but you are still giving them all of the things that make D5 amazing, just in smaller doses.
Hope that helps!