It looks like the part could easily be made with a Revolved Solid. In that case, you should probably move this discussion to the Parts and Features forum.
I don't really understand what you are trying to do. It seems like you could use Fillet features, although it might be tricky trying to get the right values that would eliminate any flats between fillets. You could use Sketch Fillets in the profile for your Revolve.You could use Arcs, particularly Tangent Arcs in your sketch. Some pictures making it more clear what you are trying to do would help.