I recommend to use PETG to print this shelf unit. I used CLOSETMAID 3/4" Tubular steel 72" Long from homedepot. You can use any ¾" tube the lenght you prefer.
Infill 40-60%
Reduce brim 1mm to fit on MK3s+
https://www.homedepot.com/p/ClosetMaid-SuperSlide-72-in-White-Closet-Rod-2058/100133925
Pair with “TOP FILAMENT ROLLER”
https://www.printables.com/model/245174-top-filament-roller
The author marked this model as their own original creation.