How would I correct this Hess cycle?
You did the right thing. However the method you used sounds confusing sometimes, it gave me a hard time too. Hess's law says that the resultant enthalpy change in a reaction is same whether it occurs in one or several steps .
We can use that to our advantage by assuming a hypothetical situation where the given reaction proceed in a number of steps for our convinience.
In your example, we disassociated $\ce{SO_2}$ molecule to corresponding standard state constituents and the enthalpy change associated with it will be $-\Delta H_f(\ce{SO_2})$.
$$\ce{2SO_2(g) + O_2(g) -&gt;[-2\Delta H_f(SO_2)] 2S(s) + 2O_2(g) + O_2(g)-&gt;[2\Delta H_f(SO_3)] 2SO_3(g)}$$
I took the following reaction through above mentioned 2 steps $$\ce{2SO_2(g) + O_2(g)-&gt;[\Delta_r H] 2SO_3(g)}$$
According to Hess law, the Enthalpy of reaction $\Delta_r H$ will be the summation of the all enthalpy changes occuring in the hypothetical intermediate steps.
$$\Delta_r H = -2\Delta H_f(\ce{SO_2}) + 2\Delta H_f(\ce{SO_3})$$