your oil cotton bud container is something i was going to design, but not for oil. Using computer printer refils or ink pad refil ink, i was going to use them to colour the filament as it fed into the extruder.
Couldnt print it as my extruder broke :( now its working, i will have a go! :-D

I've built parts like this before. What I did is I put a one layer thick wall at the tip, parallel to the next closest wall. When it got to the overhanging layer, it bridged it to my thin wall.

The thin wall was easy to cut and peel away later.

I don't like the way skeinforge does support structures. I find manually inserted ones are usually better.

Yes, this is true, I mention that problem in the youtube. When I am printing this I keep watch of the build simulation. When I see its going to print the first layer of the overhang I get a nail file and hold up the overhang, its ghetto but it works.

I played with support structures, and I think I can work one into here, but the problem is often they stick and when they stick too well, the overall printed part gets weaker, so I went without it. Then again, if you are just going to put a screw through there, probably you dont need the slot at all. I'll make the change so it doesn't have the slot.