I've a a question on brake balance.

I was to put the balance extremely to the front: 60-58 front. The setup Rick made me for Mills Metro had a (maybe standard) 52-48 distribution. Since I was used to that, I made the compromise for 56-44. And without any issues.
After settling in at Imola I tried to change it towards, 54-46, 53-47 or 52-48, but it's unstable as hell. I can manage 54-46 but not during a race. I haven't tried it on other tracks.
So I wondered whether brake balance can be track-specific or not or maybe personal?? Imola is quite weird on braking, with zones on crests, in downhill... So it might be that you need a more forward brake balance there. But I'm not sure.