I have two hills within 100 yards of my driveway. One is 0.2 miles about 9% grade. Hill 2 is 0.3 miles and is about a 10% grade. Which hill would be better? Maybe I should alternate. I also was wanting to know how to train using these hills. Should I just try to climb one of them repeatedly until I blow up? How many reps and how much effort? Thanks for the help.