I would recommend the stock gearing. You need to determine if you in fact have the stock gearing. It is rare that we are the original owners. The PO may have fiddled with the gearing.
Honda understood the torque curve of the motor and geared accordingly. What seems high reving to us but it is not since we are accustomed to the overdrives in our cars.
My K8 runs at about 5K at 70mph which has me in lower end of the power band which starts at about 4K. If you set the ratios to slow down the motor, you will lose your passing power and your engine braking. Your bike will feel sluggish on the local roads.
These motors love to rev and will run all day at 5k.