Darrsi is right when he says about the oil levels being slightly different between the Boxeye and the Foxeye.
The Boxeye has 10 millilitres (10cc) less oil per leg than the Foxeye, the reason for this is that the Foxeye Damper Rods in the base of the fork leg sliders/bottoms are shorter they are 190 mm as apposed to the Boxeyes 210 mm, the slight larger Damper Rods in the Boxeye displaces the oil a little more raising the level in the forks so the Foxeye needs the extra 10 millilitres (10cc) to make up that shortfall. Bearing in mind a house-hold teaspoon is said to hold 5cc so we are talking very little indeed, in fact two teaspoons full per leg.
10 Millilitres = 10 Cubic Centimetres, 10 ml and 10 cc are the same amount.
Again bearing in mind all these parameters are set by Yamaha with the Yamaha spring in place, the Linear Ohlins springs that I fitted was very slightly lighter in gauge so the displacement of that spring was slightly less that the Dual Rate Yamaha spring, plus, I had to take into account the Emulators that I fitted, I opted initially for 465 millilitres in each leg, hoping that the slightly lighter gauge spring would compensate for the oil displaced made by the Emulators, but I upped the oil level back to the recommended Yamaha level by 475 millilitres and found the ride to be better, but still i felt in was topping out a little when under a lot of power accelerating hard out of bends. I removed with a surgical syringe and clear capillary pipe 100 millilitres of the 15 weight oil that I used from each leg and replaced it with 30 weight oil.
I took the bike out for a ride and initially did not notice any difference but after about 30 miles or so the forks stopped topping out, due to the slightly slower damping effect of the slightly heavier oil. it took about 30 miles for the two different weight oils to mix and generally upgrade to a slightly heavier oil.
So the oil in my forks are 475 mls, made up of 375 mls of 15 weight and 100ml of 30 weight, again bearing in mind my forks are no longer Damper Rod forks but Cartridge Emulators, with the emulator set at 3 full turns in from the initial Emulator spring contact.
For me this is perfect, plenty of feel with the road, no harsh crashing out as forks plunge under heavy braking or bumpy surfaces also with the oli combination no feeling of the forks topping under hard accelerating.