I modified Laundry Detergent Cup Drain by davwilso by just slapping on a Kirkland brand screw. This really is an ingenious design by davwilso. My wife thinks this thing makes the cost of a 3d printer entirely worth it. Thanks, davwilso!
I feel like I failed to create an adapter that works well, so I decided to suck it up and just print a whole new one with a different screw.
I added a version with a lip when I noticed detergent dripping down, backwards, and eventually leaking out. I'm hoping the lip will help prevent that. This version also has a thicker screw.
Version 3 has a shorter screw because it may have previously been a bit too long. This will help with getting it secured in place.
When attaching to the laundry detergent bottle, be sure to tighten to the point where it is locked down. That will prevent the shelf from moving.
Ensure that there are no supports being printed in the channel. I set the minimum overhang angle to 60 degrees to achieve this.
Trim supports. Screw should then move freely.