I'm in love with Jesus and proud of it!
The 25k in 6 minutes DOES work. I made nearly 80k yesterday using it. However, I couldn't get the perfect checkpoint, so it was taking me 12 minutes instead of 6. Still, 80k for ~36 minutes is great.
I'm not going to be abusing this system to reach the cR cap each day. There's no point in being higher ranked if you fail in MM. Besides, at my current rate, it would take me over 6.5 hours just to get a million cR, and I'd have to set up the five challenges 40 times.