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I have quite loose fit of the small gear on the shaft of the large gear. According to the model, there is 0.45 mm tolerance in diameter of these parts which seems to be too much.
However your model looks very promising. I can imagine some detachable arm for festo fitting which could connect on either side of the stand with possibility to attach festo for PTFE tube from the front or the bottom of the arm. This would make your spool holder an universal solution with option for filament feeding from bottom of the spool (holder on table with the printer) or from top of the spool (holder on shelf above the printer with oposite direction of spool rotation).