Orient objects on surface as flat as possible (3d printing)

Hello guys,

I am very newto Grasshopper and I am reaching my limits fairly easy ^^

I am trying to make a GH File that would make building structural models easier by using a 3d-printer. In order to reduce printing time only the joints should be printed.
The basic idea is to draw only the line-modell and GH would produce the joints and orient them on a surface so they are ready to be sent to the printer.

So far I managed to create the joints but I dont know how to orient them properly onto a surface. They should rotate in a way that they are as flat as possible on the surface (printing bed)

There are 3 types of breps that shouldbe taken into consideration:
- 1. lines are planar, so these joints should be laying flat on the bed (A, B, C)
- 2. the lines are inside a half-sphere (C of Sph is the intersection point), so they can lay on the print bed with at least 2 lines/connections (D)

-3. the rest - for these its enough if they are just pulled to the surface. (E)

I tried around with different commands but the only thing I managed to do was to pull the objects to a surface and have them colliding. I wasnt able to rotate them in a useful way.