I do have Clough/Dryden. I do one to two lives per year. If there is one without a comparison, we will often decide to do one Plutarch and two Shakespeare plays. (Instead of doing both each term, we just do one of these per term, it just worked better for us.) The comparisons are often not too tough reading. Often just 3-4 pages of text. We just read it after reading the two lives.