de la Maza's article is at Chesscafe in the Archives, if you haven't seen it. Basically, the seven circles starts at ~35-40 problems a day so you do 1,000 in 32 days, then you do them in 16 days, 8 days, 4, 2, and finally 1. Its supposed to be really solid tactical drilling, but tends to favor the unemployed/independently wealthy who still have time to play while doing the Circles
How are the early levels? My daughter is 8 and has been playing for a few months and if she could handle the software's early offerings, it might be worth prioritizing its purchase over a couple of books I want.