You need to aim for 10-15mm free sag with a rider sag of around 35mm. 25mm is track stuff... and still.
Free sag too little = spring too soft
Free sag too much = spring too hard
If you want to improve the dive under braking, raise the oil level in thr fork. I will asume that you bottom out the front end... add oil until you're just shy of hitting the bump stop. Figure it out when the spring & oil is out. Using a tyrap has a travel gauge work great.
To give you an idea on my FZ09. I use 0.90kg/mm fork spring. 42mm rider sag with no preload (adjustable om the 09). Free sag is 22mm. Oil level is 130mm instead of 148mm.
That's good for the track by the way... and still comfy on the road.
Rear sag is 35mm.
Off the top; how much does the 09 weigh and how much travel does it have front and rear? Did you swap the fork springs (implied above)? I ask as it also has larger tubes with more volume.
The 6's are in the 450 lb w/ ~5" of travel front and rear.