These are oriented to print, so I recommend printing with the existing orientation.
Support settings for the base should be 65 degree overhang angle with supports touching build plate only. This will put supports only on the bottom of the base under the arched area. If you can use tree supports, you can use 45-60 degree overhang angle.
The key is printable with no supports, so you should turn off supports for the key.
I recommend at least 20% infill for the base and 100% infill for the key.
For adhesion, use skirt for base and brim for key. I recommend using tape for the key.
You may have to file the key slit open a bit at the end touching the build plate.
HOW TO USE:
Slide the bottom edge of your tube into the key slit.
Insert the tube with key into the base.
Turn the key to roll up and squeeze your tube! DO NOT OVERTIGHTEN!