I messed with different springs and had to give up because I lost track/notes as to which springs were from the carbs I had at hand>
,they are all different regrading wire diameter/coil's per inch/and overall length
In the end I bought some factory pro springs for the zx9B and used zx7r P plastic slides,a great and noticeable improvement with throttle response.
The zx9r B1 has 5mm thread main jets B2,3,4 have 6mm thread for the mains,thats the only difference with the jets apart from different jet sizes for different countries.
I also switched in different emulsion tubes, used the tubes with the higher hole count on all four carb's,the specs are in the oem manual