I saw Chuck Hellebuyck's video on Filament Friday and I printed the file he posted. But the problem in my mind was although the spool is lined up with the extruder, it causes the Ender 3 to really be too wide for my table and interferes with the space I need for my CR-10s... So I decided the best way to deal with the issue is to angle the spool horizontally at a 45 degree angle. This does two things, it allows the filament to still enter the extruder at not so steep an angle as is required by the top mounted spool holder and it allows the filament be mounted on the spool holder without all of the crazy gyrations that are required to get certain spools of filament onto the holder by avoiding the Z axis stepper motor.
Amazon Basics PLA
Depending upon the orientation you might print this with in your slicer, you may or may not need supports. I would encourage you to use a little bit of discretion and use supports if you can.