How does a mechanical braking system adjust?
All that happens at best is the rears lock up (they're unweighted) and the ABS kicks in, and you don't slow down as quick
really - you are making some pretty dumb assumptions that not only endanger your life, but the people you're about to run into.
taking the standpoint of 'uprating the fronts & rears' both at the same time is great - but unless either of you measure, test measure a whole lot more then you don't deserve to have cars.
You could buy and fit brake bias valves, but somewhere along the line, I think that might be beyond you.