When I began piecing together a 9th grade English class, I found it a challenge to select the number of books for my ds to read in a year, and to determine a logical order (not just time, but genre, themes, etc.) for the choices.
I would suggest that the easy part is finding worthy books. The WTM, Tapestry of Grace, Sonlight, the College Board web site, and a myriad of other sources and internet sites offer a wealth of choices of worthy classics for high schoolers. So I think the challenge is to narrow down the lists to a reasonable number, and provide some sort of organization and order to the four high school years.
I took a bit of an easy way out, and used the rhetoric-level lit selections recommended by TOG in the 3rd and 4th years (basically 19th century and 20th century) and, with a little substitution here and there, used those lists as my 9th grade and 10th grade lit selections.
The benefit of at least looking a rigorous curriculum like TOG -- and I believe it is top notch -- is that it helps with pacing. Trying to determine how many books to read in a year is difficult, since we don't want to overwhelm our kids, but we also want to provide a suitable rigor. By using TOG's list (and we studied 19th and 20th century history in parallel), I felt a bit more secure when my ds would "appear" inundated with work. I found that by sticking to my guns, my ds rose to the challenge. He and I found that he was capable of stepping up -- which is part of what high school requires -- in the quantity and quality of reading. So whether you USE TOG or not, I think it is a good model of what it is reasonable to expect from a high performing high school student.
A caveat to TOG -- it tends to assign more books than most programs, so there is less analysis time per book. I like that approach. I think we get enough time on each book. But if you want to spend more time talking about and writing about books, then you would want to pare down the number of books. My philosophy is "so many books, so little time," so in 9th and 10th we only spent one to three weeks on each book. ;) We have cut down the number of books a bit in 11th -- and are spending a little more analysis time on each.
I hope this helps. Best of luck! ~Brigid