That can work, though I wanted more steps, or at least more in certain parts of the IV curve.
Another thing you can do is use just one resistor and switching MOSFET in series with it, and PWM the MOSFET to get the average conductance that you want. Then you need to put an enormous electrolytic capacitor in parallel with the load and solar panel, so that the solar panel doesn't see any ripple in the current and voltage.
Both of the above are a lot easier to design and get a nice IV curve, if someone has told you beforehand quite an accurate estimate of what the current and voltage from the solar panel will be. Otherwise choosing the power resistor values is a bit tricky.