The typical human dose /kg bodyweight is pretty much the same as the horse dose /kg bodyweight.
So you can't really go wrong if you pretend you are a foal! I weigh about 87kg so I started taking from the 75 kg notch on the horse paste I had at first, but I did all the calculations based on the documentation with the paste and it was actually a bit below the 0.2 mg/kg dose so now I take doses at the 100 kg notch with no problems.