Thinner i3 mk3 spool holder

I bought a roll of filament with a 2cm hole in the middle, so the mk3 spool holder couldn't take it. I looked all over for a thinner one, but had to make one myself. This is my first try designing something :)
I have only tried printing it with 40% infill, but it looks like it works fine. The "neck" of the holder bends a tiny bit with a 600g spool on it, but nothing that worries me.
The way I printed it, I had to use supports. This made the side facing down not look 100%. I also added a support blocker for the arm in Slic3r PE, because you don't need supports on it.
Took me about five and a half hours to print this. I also used a brim, but I don't think that is necessary.

If anyone has any tips or ideas, please let me know :)