Building a DIY dry box for my more sensitive filaments, and wanted a modular spool holding solution for future dry boxes.
Printed at 0.2mm layer height, 20% infill, no supports except on "DryBoxRollerCap", PETG, since my dry box is also going to be heated. You may want to bump up infill on "DryBoxRollerCap" since that piece will be under the most stress, but so far I haven't had any issues, and as long as you're not slamming filament onto the rollers, should be fine at 15%.
My current plan is to just use some 2 sided mounting tape to affix the roller holder to the stands, the stands (at least when printed on my P1S) will press fit into the base plates, and the roller caps will press fit into the rollers, although I may increase the tolerance there, since the roller holder would still keep everything together if it was loose.
Oh, and you'll need some 608-2RS bearings. (The size that's in skateboard wheels)