IIRC, there shouldn’t be a difference using “normal to profile” when doing symmetric parts- I believe using “normal to profile” still gives you access to the “tangence influence” slider when using profiles in both directions. You usually want to increase this to 100% on the symmetry profile to help better “puff” up the surface, otherwise you can potentially get dimples or ridges when you mirror. I’ve gotten into the habit of creating the reference surface from years of modeling swoopy plastic parts. Using the surface extrude you can add draft to your reference surface (turning it into a “draft reference” surface) allowing you to build draft directly into surface features that terminate at the parting line.