William,
For a point of reference, I'm running three 46mm TB's on my n/a p-port 3-rotor, and they are working great. This is my third intake, second for the p-port engine. This is installed in a Lancair ES, so it probably has more room under the cowl that you have. If your engine isn't peripheral-ported, then you're probably better off with a single TB.
Mark S.