Conjecture on the fractional chromatic number of odd-wheel squares

Let $W_t$ be the join of the cycle $C_t$ with $K_1$, let $\chi_f(G)$ denote the fractional chromatic number of a graph $G$, and let $W_{2t+1}^{\Box 2}$ be the Cartesian square of the odd wheel. Odd-wheel fractional-chromatic-number conjecture.

$$\chi_f(W_{2t+1}^{\Box 2})=\frac{6t^2+7t+3}{2t^2+t+1}.$$

The formula is extrapolated from computations of the reduced linear program for small values of $t$; its validity for all $t$ is open.