Sfenn99- really the wrong way to look at it-
the rear of anything should not demand bigger or stronger brakes than the front-

you should look into 40 years of vehicle testing- don't know if there was ever a case where rear braking was more important than front

OP- think of it this way- get on your hands and knees and slowly decent a steep hill- you should find that the control is from your front end (hands on the ground) and not your knees sliding-

BMX and motorcross racing is all about front end control- as should be most everything- think about it a second

also- sure you can sand the pads and rotors- won't make a bit of difference if you are still going to count on the rear to control your decent

think 70% front- 30% rear