Threaded rod ends and recommendations

[CNC Brute]

My machine is 3'x 5' (2x4 cut area) in size, do you guys think I should use a dual threaded ball screw to move the gantry or a single ball screw? Or do you think I should use rack and pinion?

I am routing wood up to 1.5" thick. Etching aluminum up to .25 inch thick. And creating molds using what ever material they use for these, wax, wood, or whatever (if anyone has a supplier for these I would be most interested, plan on using it for custom halloween masks to make molds, if that helps)

Next question, My framing is 80/20, how do I mount the ball screws to this? Anyone have a link to some detailed pictures.

Thanks.