This guy should sit comfortably on your ATX PSU! Seeing as the thing takes space on my desk, might as well utilise it to my advantage. The holder should be able to house a spool that is 66mm across. (centers of spool edges), or 72.5mm overall width. The parts require support but it was easily cleaned using cura / blade. The STL has its own support for the pegs that mount the bearings - just snap those off using a pair of clippers or carefully using a blade. Bearings used are 626Z The part is made on Rhino so has no parametric features - maybe for version 2....?