The gcode files are what I printed on a standard Prusa i3 mk3 kit using Prusa’s supplied PLA plastic with almost everything left at the default settings in Slic3r Prusa Edition (v1.40.1 win64 edition).

My Spool Holder print was done with 10% rectilinear infill, 2 perimeters, and an overall height of 15mm to help keep it from breaking/bending/falling off (which is why there's the square hole in the top above where you attach it to the wood and the attachment to the wood is wider than the spool holder part). I wasn't really trying to do this, but the support triangles of the infill tended to be almost exactly where I would have put them (right at the boundaries between the support beams and the main object). It took 78 minutes and 15 grams/5m of filament (assuming standard PLA density of 1.25 g/cm^3)... which is only 3% more than if I printed with 3 perimeters and 0% infill.

The filament guide was done with 0% infill and 2 perimeters. It is designed to be printed at a height of 4 mm, but if you want to get rid of wobbling, increase the height as needed in your slicer software (or print two and bond them together using heat/positioning in the slicer software). It took 28 minutes and 3.9 grams/1.3m of filament (assuming standard PLA density of 1.25 g/cm^3).