First:
"His physical strength and speed is unmatched by most as he is able to take down a group of ninja with ease."
Second:
"He is also very intelligent able to access combat situations with great accuracy. He is also accomplished with his knowledge of jutsu, knowing their effects and drawbacks."
Third:
"His speed is greater than Kenzurai's which is no mean feat, he can clock up to 85mph on a flat plain and is very, very fast in close quarters and tight situations."
Fourth:
"Tobimaru strength is also outstanding as he is able to crush earth simply by punching it, creating small craters."
Fifth:
"But perhaps his most useful ability would be his chakra sensing. As primates have great smelling capabilities, Tobi has harnessed this to tracking and finding chakra sources. He can sense chakra from very long distances (2-3km) and from those distances he can tell how many people there are and even what species they are. Tobi can even sense how powerful ninja are by their chakra. He can sense subtle changes in the direction of chakra flow and predict movement slightly. Tobi's chakra sensing abilities puts Ninja-Hounds to shame."
All of this just from your description makes me think S-rank alone. It can take out several ninja on its own, can sense chakra and movement through that chakra, puts Ninja-Hounds to shame, can outrun an A(Maybe S) ranked shinobi who, through the wording, is already exceptionally fast, and he has earth crushing strength as well as extreme intelligence? He has so many abilities without even looking at the jutsu that I would count him as a Boss level summoning.
That plus the amount of jutsu he can utilise. I know of few summonings, cannon or otherwise, that can wield that many jutsu, even at A-rank; which pushes my judgement toward S-rank.