Looks pretty good eric! Yes, usually it's better when you have an irregular outline like this to have a broader surface that then gets cut by the outline rather than trying to build a new surface directly through something that does not have some regular shape.

You can also use the Edit > Trim command for doing that - Trim has projection built into it so you can skip some steps, instead of projecting the curve onto the site surface as a separate step, you can select the site surface, run Edit > Trim and then pick the 2D curve as the cutting object and that should then project the 2D curve onto the site surface and use it to cut the site surface as well.

- Michael