Low Friction Feed for keeping filament dry

According to https://www.youtube.com/watch?v=ACRh51hdBxo, there are two key attributes needed to print flexible filament like TPU successfully. (1) Keep the filament dry, and (2) Feed it with the lowest possible friction into your Extruder.

The Roller Holder is a two-part system using four Skate Bearings to support the roll of filament. This is more-or-less standard practice. But I think it's fine to leave the surface of the rollers "flat" and constrain the lateral position of the spool by