You probably want to test the cars/couplers on the planned curve.
Generally the issue with body mount is not going around the curve it is coupling automatically on curves. With body mount, you need really wide curves or just couple on straight sections.
Even in HO guys with 30 inch radius canot often couple on curves this would be equal to 60 inch radius or so in O.
So the way you plan to use the curves may very important to what radius you can handle. A train will stay coupled on pretty sharp curves that will not accomodate unassisted coupling.