Guy proved himself to be stronger than Kakashi when a worn out version of himself outsped Madara's Onmyoton balls, whilst carrying Kakashi, in a Gate lower than the 7th (it may have even been lower than the 6th seeing that his pupils were still visible afterwards). The mere fact that he can outspeed an attack faster than Kamui while worn out and carrying someone implies that he can replicate the same feat in Gate 6 (maybe even Gate 5) in a match against Kakashi.
And if Guy can outspeed Kakashi's fastest attack, then Kakashi doesn't have much of a chance of winning, especially with the sheer amount of range and destructive capacity that Morning Peacock possesses. Gates 7 (surprising and pressuring Juubi Madara with his speed, who casually counterattacked a FTG-aided blitz from a SM enhanced Minato) and up would be overkill.
And if Guy can outspeed Kakashi's fastest attack, then Kakashi doesn't have much of a chance of winning, especially with the sheer amount of range and destructive capacity that Morning Peacock possesses. Gates 7 (surprising and pressuring Juubi Madara with his speed, who casually counterattacked a FTG-aided blitz from a SM enhanced Minato) and up would be overkill.