I wanted to be able to mount an external spool and modified the design of this riser setup that I use. This allows an external spool to fit on the right hand side of the printer.

You'll need to add tree supports for the filament guide part, but not for the spool holder mounting.

The hole is designed at 9.5mm for a PC4-M10 fitting, but only screw it in by hand, if it's too tight you'll need to drill or file the hole out slightly.

The original guide for this model uses Lightening supports but I would recommend cube or grid infill at least 15% or else the spool holder will flex too much when a 1kg spool is fitted.