| ?? You can go over 10% usually, if you want to.
There are two ways of controlling the CO. The trimmer in the ecu itself is a global adjustment. It alters both cylinders.
You then need to tweak the air bypass screws to bring both cylinders in together.
These are the two you closed when balancing the throttles.
Screwing them out will weaken the relative cylinder, screwing them in richens.
A good start to get both the cylinders the same is 1/4 out on the front and 3/4 on the rear. The rear always runs a little richer, although less so with the FIM eproms.
Get the front to 4% or so with minimal bypass using the trimmer and then pull the rear down with the bypass screw as required. | 
Threaded Mode