15" Steering Wheel - Vs. - 13" Steering Wheel ?

With a manual steering box, in a 65 Valiant, or similar, tight turning with a 13" steering wheel is difficult. -- Has anyone switched from a 13" wheel to a 15" wheel, and if so, what has been you experience, as to feel, to turn, in tight situations - parallel parking etc. ? -- It seems that the extra leverage, with a 15" wheel, would help.