The situation:
JDM diff/rear end, rest of the brake system is ADM. I have a JDM brake proportioning valve sitting here in anticipation of putting something a bit beefier on the fronts. I've noticed that the rear wheels get dirty from brake pad dust quite a bit quicker than the fronts, which is my (probably dumb) reasoning for asking these questions:

Is there an easy way (apart from locking up the brakes at speed) to tell if my F/R bias is "correct"?

What IS the correct balance F/R? (60f/40r?)

Pretty much trying to work out if I should install this JDM valve now, or wait until I upgrade the front, which could be a few months off.

Thanks,
-B.