I modified the MK4 filament guide which had already been modified to allow the use of a bowden tube, to also provide more space between the guide and the filament spools. This will allow use of a centering hub, for example this one that I designed, to fit. The stock MK4 guide was too close to the holder for the spools to fit otherwise.
The author remixed this model.
Increased distance from spool holder.