They are suitable to use with t-nuts and L-brackets. You can save time printing it in vase mode (see printing notes) or you can use your favorite printing settings.
Scale Z height depending on your needs and print vertically
Unlike other slicers, you can determine shell thickness, even in vase mode, in Cura(15.04) easily. You can find my settings below.
Layer height: 0.2 mm
Shell thickness 0.8 mm
Expert config --> Spiralize the outer contour (checked)
--> Solid infill top (unchecked)
--> Solid infill bottom (unchecked)
Check other 2020 and 2040 profiles,
Now you have the connectors :)