Some consideration of Surface Editing...

First off, when you cannot have proper shapes in Surface Edit mode, turn up the "Surface Tessellation" amount.

This affects tessellation for display purpose only, I believe.

Extruded a bezier wire. This body consists from ten faces; two Planar Faces (cap ends) and eight Spline Faces.

Click with [Convert To NURBS Body] tools in [Body Editing] palette. Then, all faces are converted to Spline.

Set the pick filter to [Face], and select all faces with [Pick] tool. Then, select [Edit Surface] tool. Now you can edit eight faces in side alright, but not the cap ends. These two faces seem to lose boundary information in Surface Edit mode. Very disappointing...

So, let's think about side faces now. As for the cap ends faces, I will talk later...

Before you edit multi-face surface, you have to select all faces with [Pick] tools. It's tedious, don't you think? I prefer to separate the faces. Of cource you can use [Unhook Faces] tool, but there's easier approach...

Set the pick filter to [Face], and select all faces with [Pick] tool. Then, type [command]+[D] to duplicate the selected faces.

Now you have single-face sheet bodies. You can edit them separately, or [N]+click with [Surface Edit] tool to edit simultaneously.

 

What about front and back faces?