You'd have to play around with the balances and pull your FICO score to see the changes. Ideally, you want 1/2 reporting $0 and the other 1/2 reporting a balance of 9% or less. If I got it to that baseline, then I personally would experiment w/ 1 reporting a balance, then 2 , 3, etc. based on the number of CCs reporting now all the way up to 1/2. And based on the higher score, I'd then tweak it to 1%, 2%, 3%, etc. just to see which levels produced the highest score. It really boils down to a few points extra, but every little bit helps. In short, there is no hard rule on this. YMMV.