I also like this pot. It's got some nice patina starting to form!
There are two things however, Tousui is a Seto-ware potter, not Tokoname, like his father and uncle, both also very famous potters. The other thing is, I don't recognize this chop as the modern Ryukujan Tosui, so it could be his father, the patina definitely looks it.
Definitely not Kazuhiro, either in his original 4 Character cartoony stamp, or the later 3 when "Kazuhiro" was misread in the hanko by a dealer as "Ikkou," which became the popular name for his pots, so he changed it to Ikkou.
The first two characters in this Chop read Tosui, so im inclined to believe your dealer, the second two I'm not sure.