Need advice on Boundary Boss/Base

I am essentially trying to create a component similar in size and shape to male jock/cup. What is the best way to create this model? Is it using boundary boss/base?

How do I get the profile of the center spline to follow the base profile. I have attached an e-drawings file of the sketch geometry and one of a rough model using several planes and sketches. I need it to be much smoother and fill the entire profile.

SolidworksParts And Features