Welcome to the confusing world of the Chinese. There are two types of Mikuni. The real Japanese one that you linked, and the Chinese copy I have. The real one has the mixture screw on the side. Mine has the mixture screw underneath and is bit fiddly, but can be reached with a small screwdriver.
It gets even more confusing as they call it a 26mm, but is really is a 22mm.
Since it is a 22mm venturi size carb, it is the same size as the original deni one, no ?
I found this one today
. Looks like the stock deni pz26 but one size bigger.