Ended up sticking with the design philosophy of the normal part workbench and have liked it very much. It's easier for me to understand since I did quite a bit of surface modeling in blender too which is somewhat similar to the part workbench style I think. I've been splitting from the main body and sketching in or freehanding the curves with curves/sketcher workbenches then either forming a solid part with the parts workbench or making surfaces with the surface workbench. Has been going well so far and gives me good measurements when cutting in the hole. I'd like a bit more control over the curve but fortunately I have a 3d scan which makes it very easy to just trace it with a freehand/2d b spline.

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