As discussed in my previous design "Funnel on pipe design", the existing brackets seems safe in stress, but there are possibilities of failure over time, due to wearing, shock loading or fatigue, but still if you wish to continue with the existing bracket, I recommend add new brackets between the existing brackets, besides I do not recommend spool holder mounted at the edge of the brackets as this will produce more overhange, leading a higher amount of torque to either break or remove the brackets.
This new design will require 9 bearings, which I took from figit spinner, having ID 0.25in, OD 0.75in & 0.25in wide, 4 for spool mount, 3 for pulley system near the spool & 2 at the machine, so you have to multiply as per your requirement.
A screw 6-32 X 1/2in long, other screw are to mount pully system on my machine, this will vary.
I recommend to print all parts with ABS or stronger material with 100% fill.
For assembly, I have attached 3D PDF & CAD file.