ANET A8 SpoolHolder

I started out with the spoolholder from - Madjestik58 Jun 13, 2016 - but I had my concerns about the weight on top of the display wiggeling around which effects the print quality.
The original spoolholder was taking up a lot of space behind the printer and I had to carry the printer and the spoolholder separately. So I came up with this design to mount it tight to the back. My contribution are only the two blue parts (LeftArm, RightArm) printed in PLA the rest of the complete spoolholder is from Madjestik58.
The white pieces are printed with PETG and they have better properties in relation to PLA!
In general I prefer printing in PETG and I have no difficulties whatsoever.
The 3D design is accomplished in DesignSpark Mechanical and the related files are attached in addition to the STL files.
I print with PLA/PETG with 235 degree (yes - both the same temperature)
I use Cura 2.6 with 0.2mm draft mode. 1.5 wall thickness, InFill Density 25%.
I'm not the greatest 3D part designer/pri