I am not doing the "rotation", but usually just add the 100 rep challenges in as time permits. They are usually less than 10 mins in length, so they are an easy add on.
I use them to compliment my activity for the day. i.e.... today I did PURE Strength Biceps/Back/Abs and because the length was a little shorter I had time to complete the 100 rep Bicep AND the 100 rep Scarecrow Challenges.