For complex curves there is one way I usually use.
1) Create a sketch with the wanted profile and constrain it
2) Create an other sketch on the same plane as the first one. Use "project" to add in the profile from the first sketch (think it´s called exract in the earlier UG). Now you can use "offset exracted curves". Convert the original curves to reference so they don´t interfere in your future work.
I recommend that you use an user definied expression for the offset value, you will not get a feature in the MN. The offset is only editable through expression.
