In theThe answer to another question : (Upper bound of the fraction of Gamma functions the) gave an asymptotic upper bound for the fraction ofan expression with Gamma functions have been established: $$\left(\frac{\Gamma(a+b)}{a\Gamma(a)\Gamma(b)}\right)^{1/a}\leq C\cdot f(a,b), \forall a,b\geq1/2$$.$$\left(\frac{\Gamma(a+b)}{a\Gamma(a)\Gamma(b)}\right)^{1/a}\!\leq \,C\,\frac{a+b}a, \forall a,b\geq\frac12$$
What is a non-asymptotic boundthe best possible value for this ratio, i.e. what is the constant $C$ in that statement?