I want the profile shown below which is drawn on the XY...

To follow this arc in the XZ plane...

...as a spline. Is there a simple way of doing this?

I'm wanting to use a "lofted boss" feature to create a more complex version of the geometry shown below. This was created by extruding the sketch labeled "A" and then doing a "revolve cut" of sketch "B".

I can acquire the desired spline by doing a "fit spline" of the edges of the geometry created.

Below is a dummy version of the desired end result. I'd like to accomplish this using just the "lofted boss" feature. The profile is the easy part, I just can't for the life of me figure out how to properly define the spline for the curve.

Thanks for any help, and have a great day.