Dean,
Thank you very much for your help I really appreciated.
Smart way to increase the cutting area and add future use(4th axis)

Few questions and I think I am good to go.

Steel tubing for the whole base 60 x 60 x 5 ? Do you agree on that?

Length of the bed 2600 + 100 short overhang + 300 long overhang = 3000 total would that be o.k? Do the overhangs need to be braced?

What are the spacing of the cross members and the top rail supports in your drawings? No dimensions so I can't calculate.

Has anyone joined hiwin rails lengthwise let's say 1500 + 1500 to achieve 3000mm length. Is it doable for the home builder? ordering from BST automation 3000mm rails will make shipping cost way up.

Hopefully I will be start building in the beginning of January.