I accidentally erased your post on the hydrolysis of various anions. The answer is

Kb(for the anion) = (Kw/Ka for the Ka for the acid) where Ka will be Ka for monoprotic acids, k2 for diprotic acids, or k3 for triprotic acids
So to make OH^- the smallest you want Ka to be the largest. For example,
........CO3^2- + HOH ==> HCO3^- + OH^- so Kb for CO3^2- is
Kb for CO3^2- = (Kw/k2 for H2CO3) = (x)(x)/(CO3^2-). Therefore, for OH to be the smallest you want Kw/Ka to be the smallest which makes Ka the largest.