Hi, i only had a m5x20 screw so i made a remix that gets rid of the wasted space so it works. To get the Nut in you can just put it vaguely in the right spot and than hammer it in with the screw flipped.
About the Print Settings: Don't fall for the 100% Infill Meme, I'd advice you to add more shells instead since that will make it actually stronger. In Cura i put my wall line count to 6 and top and bottom to 5 while having 70% infill. You could probably go lower but i wasn't there to fiddle around.
Also i printed this with the 240° to make the layers bind better together, same reasoning goes for 0.32 layer height.
To align it correctly just make sure the pulley is pushed in all the way and you are good.
DAS Filament PLA
It was a little bit dirty afterwards ;_;