I designed this simple mount to attach the spool holder that comes with a CR-10 to the frame. I've mounted mine at the top. You do not need to modify any parts, but you do need 2 screws with T nuts to attach it to the frame. I used M5-0.80 x 12mm button head screws with M5 T nuts for 20mm slots.
I found that having the filament spool mounted on the control box would break the filament if left on it. While mounted up top, I can be lazy and leave a spool attached, and the filament won't break.